There are over a dozen image formats you'll encounter regularly, and each one exists because it solves a problem the others don't. Knowing the difference between lossy DCT compression and lossless DEFLATE isn't academic trivia — it's the difference between a 2MB product image and a 25MB one.
This reference covers every image format that ChangeThisFile supports, with the technical detail that actually matters: how compression works, what color depths are available, where browser support stands, and when you should choose one format over another. No hand-waving — real specs and real tradeoffs.
Master Comparison Table
| Format | Compression | Lossy/Lossless | Transparency | Animation | Max Colors | Typical Use |
|---|---|---|---|---|---|---|
| JPEG/JPG | DCT | Lossy | No | No | 16.7M (24-bit) | Photos, social media |
| PNG | DEFLATE | Lossless | Yes (8-bit alpha) | APNG variant | 281T (48-bit) | Screenshots, logos, graphics |
| WebP | VP8/VP8L | Both | Yes (8-bit alpha) | Yes | 16.7M (24-bit + alpha) | Web delivery |
| GIF | LZW | Lossless* | Binary (1-bit) | Yes | 256 (8-bit indexed) | Animations, memes |
| BMP | None/RLE | Lossless | Some variants | No | 16.7M (24-bit) | Windows legacy, raw pixel data |
| AVIF | AV1 | Both | Yes (8-bit alpha) | Yes | 1B+ (10/12-bit) | Next-gen web, HDR |
| ICO | PNG or BMP inside | Both | Yes | No | 16.7M (32-bit RGBA) | Favicons, Windows icons |
| SVG | N/A (vector) | Lossless | Yes | Yes (SMIL/CSS) | Unlimited | Logos, icons, illustrations |
| TIFF | Various | Lossless | Yes | Multi-page | 281T (48-bit) | Print, archival, scanning |
| HEIC/HEIF | HEVC | Both | Yes | Yes (Live Photos) | 1B+ (10-bit) | Apple device photos |
| PSD | RLE + internal | Lossless | Yes (layers) | Timeline | 281T (48-bit) | Photoshop editing |
| JPEG XL | VarDCT/Modular | Both | Yes | Yes | Billions (32-bit float) | Photography, archival |
* GIF's LZW compression is technically lossless, but the 256-color palette forces color quantization from the source, which is a form of quality loss.
JPEG / JPG
The Joint Photographic Experts Group format, universally known as JPG, has been the internet's default photo format since the early 1990s. It's supported literally everywhere — every browser, every phone, every email client, every image editor, every printer.
Technical Details
JPG compression works in stages: color space conversion (RGB to YCbCr), chroma subsampling (reducing color resolution — human eyes are less sensitive to color than brightness), 8x8 block DCT, quantization (the lossy step), and Huffman entropy coding.
Progressive vs Baseline: Baseline JPG loads top-to-bottom. Progressive JPG stores multiple scans of increasing detail, so the full image appears blurry first, then sharpens. Progressive files are typically 2-5% smaller than baseline at the same quality and provide better perceived loading speed. Most modern encoders default to progressive.
EXIF metadata: JPG files carry EXIF data — camera model, GPS coordinates, exposure settings, timestamps. This metadata can be 10-500KB. For web delivery, stripping EXIF saves bytes and protects privacy (GPS data). For archival, keep it — it's the only record of how the photo was taken.
Quality factor: JPG quality is a 0-100 scale, but it's not standardized across encoders. Photoshop's quality 8 (out of 12) is roughly equivalent to ImageMagick's quality 85 (out of 100). Always test output quality visually rather than trusting the number.
Convert WebP to JPG | Convert PNG to JPG | Convert HEIC to JPG
PNG
Portable Network Graphics was created in 1996 as a patent-free replacement for GIF after the LZW patent controversy. It surpassed GIF in every technical dimension except animation — and even that was later addressed by APNG.
Technical Details
Color types: PNG supports five color types, each for different use cases:
- Grayscale (type 0) — 1/2/4/8/16-bit, no color information
- Truecolor RGB (type 2) — 8 or 16 bits per channel, 16.7M or 281T colors
- Indexed (type 3) — 1/2/4/8-bit palette, max 256 colors. This is where PNG excels for simple graphics — a 20-color diagram as indexed PNG can be under 10KB
- Grayscale + Alpha (type 4) — 8 or 16 bits per channel, with transparency
- Truecolor RGBA (type 6) — 8 or 16 bits per channel, with full alpha transparency
Chunk structure: PNG files are organized as typed chunks (IHDR, IDAT, IEND, etc.). This extensible design allows metadata (tEXt), color profiles (iCCP), and timing info (acTL for APNG) without breaking backwards compatibility.
Interlacing: Adam7 interlacing stores pixels in 7 passes of increasing resolution. Like progressive JPG, this allows a low-res preview to appear before the full image loads. The downside: interlaced PNGs are typically 5-10% larger than non-interlaced.
Convert JPG to PNG | Convert WebP to PNG | Convert BMP to PNG
WebP
Google released WebP in 2010 as a web-optimized format derived from the VP8 video codec. It took 10 years to achieve full browser support (Safari was the last holdout in 2020), but in 2026 it's the standard recommendation for web image delivery.
Technical Details
Lossy mode (VP8): Uses variable-size block prediction (4x4, 8x8, 16x16) with adaptive quantization. The variable block size is the main reason WebP outperforms JPG — it can use larger blocks for uniform areas and smaller blocks for detail, instead of JPG's fixed 8x8 grid.
Lossless mode (VP8L): An entirely separate codec using spatial transforms, color caching, Huffman coding, and backward reference. Lossless WebP files are 25-30% smaller than PNG for photographic content. The gap closes for already-simple images where PNG's DEFLATE is already efficient.
Alpha compression: WebP compresses the alpha channel separately using a lossless method, even in lossy mode. This means you can have lossy RGB data (small file) with a perfectly sharp alpha mask (clean edges). PNG can't do this — it's all-or-nothing lossless.
Animation: Animated WebP uses frame differencing and disposal methods similar to GIF but with VP8/VP8L compression. Animated WebP files are typically 30-50% smaller than equivalent GIFs. Google's own data shows animated WebP is 64% smaller than GIF on average across their test corpus.
Limitations: Maximum dimension is 16383x16383 pixels. No support for color depths above 8-bit per channel. No HDR or wide color gamut (use AVIF for that). Encoding is slower than JPG — roughly 5-10x slower at equivalent effort.
Convert PNG to WebP | Convert JPG to WebP
GIF
Graphics Interchange Format dates to 1987 and technically should have been replaced by APNG or animated WebP years ago. It hasn't been, because the internet collectively decided GIF means "short looping animation" and no format name is going to change that.
Technical Details
LZW compression encodes repeating patterns in the indexed pixel data. GIF is limited to a 256-color palette per frame, selected by quantizing the full-color source. This quantization is where quality loss occurs — complex photographs get dithered into a 256-color approximation that looks awful.
Animation: GIF stores multiple frames with per-frame delay timing and disposal methods (don't dispose, restore to background, restore to previous). The format was never designed for video — there's no inter-frame compression. Each frame is independently compressed, which is why a 3-second GIF can easily be 10MB while the equivalent MP4 is 200KB.
Transparency: GIF supports binary (1-bit) transparency only — each pixel is either fully transparent or fully opaque. No semi-transparent pixels, no anti-aliased edges against transparent backgrounds. This creates jagged edges when placed on different background colors.
Why GIF survives: Universal platform support (every messaging app, social platform, and email client), simple autoplay behavior, and cultural momentum. For actual use cases requiring animation, converting GIF to MP4 reduces file size by 90%+ with better quality.
BMP
Bitmap Image File is Windows' native image format, dating back to Windows 1.0 in 1985. It stores pixel data with minimal compression, making files enormous but trivial to parse.
Technical Details
Compression options: Most BMPs are uncompressed — raw pixel data with a header. RLE (Run-Length Encoding) compression is available for 4-bit and 8-bit BMPs but rarely used. There's no equivalent to JPG's DCT or PNG's DEFLATE.
Color depths: BMP supports 1-bit (monochrome), 4-bit (16 colors), 8-bit (256 colors), 16-bit (65K colors with various channel layouts), 24-bit (16.7M RGB), and 32-bit (16.7M RGBA). The 32-bit variant includes alpha transparency, though software support for BMP alpha is inconsistent.
File sizes: An uncompressed 1920x1080 24-bit BMP is exactly 5,760 KB (1920 x 1080 x 3 bytes + header). No compression means the file size is entirely predictable from dimensions and color depth. A 4000x3000 photo is 36MB as BMP versus 2.8MB as JPG.
When you'll encounter BMP: Windows screenshots (some older tools default to BMP), legacy enterprise applications, raw pixel data from image processing pipelines, and occasional use in embedded systems where decompression speed matters more than file size. Convert to PNG for lossless or JPG for lossy: BMP to PNG | BMP to JPG.
AVIF
AV1 Image File Format is derived from the royalty-free AV1 video codec, developed by the Alliance for Open Media (including Google, Apple, Mozilla, Netflix, and Amazon). It's the most technically advanced raster image format in widespread use.
Technical Details
Compression: AVIF uses AV1 intra-frame coding, which applies block partitioning with sizes from 4x4 to 128x128, directional intra prediction (56 angles vs JPG's none), and a sophisticated transform coding pipeline. The result is files 20-30% smaller than WebP and 50%+ smaller than JPG at equivalent quality.
Color depth: 8, 10, or 12 bits per channel. 10-bit AVIF is the sweet spot for HDR photography — it provides 1,024 tonal steps per channel (vs 256 for 8-bit formats), eliminating banding in gradients and shadows. This is AVIF's killer feature over WebP and JPG.
HDR support: AVIF natively supports PQ (Perceptual Quantizer) and HLG (Hybrid Log-Gamma) transfer functions for HDR content. It can embed HDR10 metadata and wide color gamut profiles (BT.2020). No other widely-supported web image format handles HDR this well.
Browser support (2026): Chrome (since 85), Firefox (since 93), Safari (since 16.0). Edge follows Chrome. That's roughly 92-94% global coverage. The gap is older Safari/iOS versions and some embedded browsers.
Encoding speed: AVIF's main drawback. Encoding is 10-50x slower than JPG and 5-20x slower than WebP at comparable settings. A 12MP photo takes 2-8 seconds to encode as AVIF versus 100-200ms for JPG. This makes real-time conversion impractical for high-volume pipelines without dedicated hardware.
Convert AVIF to JPG | Convert AVIF to PNG
ICO
ICO is a container format designed for Windows icons and web favicons. It's not really an image format — it's a multi-resolution wrapper around PNG or BMP images.
Technical Details
Structure: An ICO file contains a directory of one or more images at different resolutions. A typical favicon.ico includes 16x16, 32x32, and 48x48 versions. The browser or OS picks the most appropriate size. Each contained image can be either BMP or PNG format — modern ICOs use PNG for better compression.
Favicon usage: While modern browsers accept PNG, SVG, and other formats for favicons via <link rel="icon">, the /favicon.ico file at the site root is still checked by default. For maximum compatibility, provide a multi-resolution ICO at /favicon.ico and a PNG or SVG via the link tag.
Size limits: ICO images max out at 256x256 pixels per image in the directory. For larger icons (like macOS .icns), you need a different format entirely.
Convert PNG to ICO | Convert SVG to ICO
SVG
Scalable Vector Graphics is the only widely-supported vector image format on the web. Unlike every other format in this guide, SVG doesn't store pixels — it stores mathematical descriptions of shapes, paths, and text.
Technical Details
XML structure: SVG files are plain-text XML. A circle is <circle cx="50" cy="50" r="40" fill="red" />. This means SVGs can be edited in a text editor, manipulated via JavaScript DOM APIs, styled with CSS, and generated programmatically.
Scalability: Because shapes are defined mathematically, SVGs render perfectly at any resolution. A 2KB SVG logo looks sharp on a 4K display, a phone screen, and a billboard. No raster format can match this — you'd need a massive PNG or JPG for each target size.
File size: For simple graphics (logos, icons, illustrations), SVG is incredibly compact. A logo that's 50KB as PNG might be 3KB as SVG. But SVGs containing complex paths (traced photographs, detailed maps) can become enormous — a vectorized photograph might be 2MB as SVG versus 200KB as JPG. SVG is for graphics that were designed as vectors, not for rasterized content.
Security: SVGs can contain JavaScript via <script> tags, external resource references, and CSS that loads remote fonts. When accepting SVG uploads from users, you must sanitize the XML to prevent XSS attacks. Never serve user-uploaded SVGs with an image/svg+xml content type without sanitization.
Need a raster version? Convert SVG to PNG | Convert SVG to JPG
TIFF
Tagged Image File Format is the print and publishing industry's workhorse. You'll rarely encounter TIFF on the web, but it's essential in professional photography, scanning, medical imaging, and print production.
Technical Details
Tag-based structure: TIFF uses a tag system (Image File Directories) where each tag describes an aspect of the image — dimensions, color space, compression, resolution, etc. This makes TIFF incredibly flexible but also means TIFF files can be structured in countless ways, and not all software reads all TIFF variants.
Compression options: TIFF supports no compression, LZW, ZIP (DEFLATE), PackBits, JPEG compression, and others. Uncompressed TIFF is common in print workflows where lossless quality and fast random access matter more than file size.
Multi-page: TIFF supports multiple images in a single file — useful for scanned documents, fax archives, and multi-frame scientific data. This is why many scanners default to TIFF output.
Color depth: Up to 16 bits per channel (48-bit RGB or 64-bit RGBA), plus support for CMYK (print color space), Lab color, and floating-point pixel values. This high bit depth makes TIFF the preferred archival format for professional photographers who need maximum editing latitude.
File sizes: Enormous. An uncompressed 12MP TIFF is 36MB (same as BMP). With LZW compression, roughly 15-25MB. TIFF is not for the web — convert to JPG or WebP for web delivery: TIFF to JPG | TIFF to WebP.
HEIC / HEIF
High Efficiency Image Container (HEIC) uses HEVC (H.265) video compression for still images. Apple adopted it as the default camera format on iPhones starting with iOS 11 (2017), making it one of the most-produced image formats in the world.
Technical Details
HEVC compression: HEIC applies the same compression used in H.265 video to individual images. It produces files roughly 50% smaller than JPG at equivalent quality — a 12MP iPhone photo is about 1.5MB as HEIC versus 3-4MB as JPG.
10-bit color: HEIC supports 10-bit color depth, providing 1,024 tones per channel versus JPG's 256. This matters most in gradients and shadows, where 8-bit JPG shows visible banding.
Live Photos and bursts: HEIF (the container format) can store image sequences, making it Apple's format for Live Photos (still + short video) and burst photography. A single .heic file can contain multiple images with different roles.
The compatibility problem: HEIC is Apple-centric. Windows added native support in Windows 10 (via a store extension), Android added partial support in Android 9, but web browsers have zero native HEIC support. You cannot display a .heic file in any browser. Sharing HEIC photos outside the Apple ecosystem always requires conversion.
Patent situation: HEVC is patent-encumbered (MPEG-LA licensing), which is why Google pushed WebP/AVIF (royalty-free) instead. This patent situation also limits HEIC's adoption in open-source software.
Convert HEIC to JPG | Convert HEIC to PNG | Convert HEIC to WebP
PSD (Photoshop Document)
PSD is Adobe Photoshop's native file format. It's not designed for image delivery — it's designed for preserving the full editing state of a Photoshop project, including layers, masks, adjustment layers, smart objects, text, and blending modes.
Technical Details
Layer preservation: The primary reason PSD exists is to maintain non-destructive editing capability. A PSD with 20 layers, masks, and adjustments can be re-opened in Photoshop with full editability. Exporting to any other format (PNG, JPG, WebP) flattens these layers permanently.
Color modes: PSD supports RGB, CMYK, Lab, Grayscale, Bitmap, Duotone, and Indexed Color. 8-bit and 16-bit per channel. 32-bit float for HDR editing. This makes PSD the most color-capable format in this guide.
File sizes: Large. A PSD with multiple layers at 3000x4000 resolution easily reaches 100-500MB. The maximum canvas size is 300,000 x 300,000 pixels, and the max file size is 2GB (or 4GB with PSB, Large Document Format).
When you'd convert FROM PSD: When a designer hands you a PSD and you need a web-ready image. Flatten it to PNG (lossless, preserves transparency) or JPG (photos). Don't convert PSD to WebP directly if you need to preserve quality — go PSD to PNG first, then PNG to WebP, to have a lossless intermediate.
Convert PSD to PNG | Convert PSD to JPG
RAW Formats (CR2, NEF, ARW, DNG)
RAW is not a single format — it's a category. Every camera manufacturer has their own proprietary RAW format: Canon uses CR2/CR3, Nikon uses NEF, Sony uses ARW, Fuji uses RAF, and Adobe created DNG as an open standard.
RAW files contain minimally processed sensor data with the full dynamic range and color depth the camera captured — typically 12-14 bits per channel versus JPG's 8. A 24MP RAW file is usually 25-60MB.
ChangeThisFile supports converting common RAW formats to standard image formats. You can convert Canon CR2 to JPG, convert Nikon NEF to JPG, or convert Sony ARW to JPG. The conversion applies a default demosaicing and tone mapping to produce a usable image. For professional control over white balance, exposure, and color, use a dedicated RAW processor like Lightroom or Capture One before converting.
Choosing the Right Format
Here's the short version:
- Web delivery (general) → WebP with JPG fallback
- Web delivery (HDR/high-quality) → AVIF with WebP fallback
- Photos for sharing (email, messaging) → JPG at 85-92% quality
- Photos for print → JPG at 95%+ or TIFF (ask the print shop)
- Screenshots and UI graphics → PNG (indexed if few colors, RGBA if transparency needed)
- Logos and icons → SVG (vector) or PNG (raster), ICO for favicons
- Animations (short loops) → Animated WebP or GIF for compatibility, MP4 for quality/size
- Archival (maximum quality) → PNG (16-bit) or TIFF (uncompressed/LZW)
- iPhone photos for non-Apple recipients → Convert HEIC to JPG before sending
Every format in this guide exists because it solves a specific problem. JPG solved photo compression in 1992 and still dominates because nothing else is as universally supported. PNG solved lossless transparency. WebP solved web performance. AVIF solves HDR. SVG solves scalability. Understanding which problem you're solving tells you which format to use.
Need to convert between any of these formats? ChangeThisFile handles them all: HEIC to JPG, PSD to PNG, SVG to PNG, GIF to MP4, and 600+ other routes — free, no signup, most running entirely in your browser.