Choosing the wrong image format costs you — bloated file sizes slow your website, wrong compression destroys your design work, and incompatible formats mean your images simply don't display where they need to.
Quick Decision Guide
Before we dive deep, here is the short version:
Photographs for the web → JPG (or WebP for modern browsers). Logos, icons, and graphics with transparency → PNG (or SVG for scalable). Web performance priority → WebP or AVIF. Scalable graphics and illustrations → SVG. Simple animations → GIF (or animated WebP). Print and archival → TIFF. iPhone photos you need to share → Convert HEIC to JPG.
PNG — Portable Network Graphics
PNG is the workhorse of web graphics. It uses lossless compression, meaning no image data is lost when you save. This makes PNG ideal for logos, icons, screenshots, text-heavy graphics, digital illustrations, and anything requiring transparency.
A photo saved as PNG will be 5-10x larger than the same photo as JPG, with no visible quality difference. If your image is a photograph, JPG or WebP will serve you better.
Key specs: Lossless compression, full alpha transparency, up to 48-bit colour, universal browser support.
Need to convert PNG? Convert PNG to JPG to reduce file size, convert PNG to WebP for web performance, or convert PNG to SVG for scalable vector output.
JPG (JPEG) — Joint Photographic Experts Group
JPG is the most widely used image format in the world. It uses lossy compression to achieve dramatically smaller file sizes. For photographs, the quality loss at reasonable compression levels is virtually invisible.
Use JPG for photographs, product images, portraits, landscapes, food photography, email attachments, and social media. Avoid JPG for logos, text, screenshots, or graphics with sharp edges — compression creates visible artifacts around sharp transitions.
Key specs: Lossy compression (adjustable 1-100%), no transparency, 24-bit colour, universal support.
WebP — Google's Modern Format
WebP supports both lossy and lossless compression, plus transparency and animation. Files are 25-35% smaller than equivalent JPGs and PNGs. WebP should be your default for any web-destined image.
Key specs: Both lossy and lossless, transparency support, animation support, all modern browsers.
SVG — Scalable Vector Graphics
SVG is fundamentally different — it is a vector format using mathematical shapes, not pixels. SVG images scale to any size without quality loss. Use SVG for logos, icons, illustrations, charts, and diagrams.
SVG files are code (XML) that can be styled with CSS and animated with JavaScript. Do not use SVG for photographs.
GIF — Graphics Interchange Format
GIF is the internet's animation format. Created in 1987, it supports up to 256 colours and simple animation. Use for short animations and reaction images. For better quality animated content, consider animated WebP.
Key specs: 256 colours max, binary transparency, animation support, universal.
BMP and TIFF
BMP stores raw pixel data with no compression — rarely used in modern workflows. TIFF is the professional standard for print, archival, and medical imaging with lossless compression and CMYK support.
AVIF and HEIC — The New Formats
AVIF achieves up to 50% smaller files than JPEG at equivalent quality. Browser support is growing rapidly. HEIC is Apple's default iPhone photo format since iOS 11 — stores photos at half the size of JPG. Convert HEIC to JPG for universal sharing.
The Complete Comparison
PNG: Lossless, transparency, medium size, best for graphics. JPG: Lossy, no transparency, small size, best for photos. WebP: Both, transparency, smaller, best for web. SVG: Vector, scalable, tiny, best for icons. GIF: Lossless, animation, medium, best for short clips. TIFF: Lossless, large, best for print. AVIF: Both, smallest, best for modern web. HEIC: Lossy, small, best for iPhone.
Frequently Asked Questions
What is the best image format for websites?
WebP offers the best balance of quality and file size for modern websites. Use WebP as your primary format with JPG as a fallback.
Can I convert between formats without losing quality?
Converting between lossless formats preserves full quality. Converting from lossy to lossless preserves current state but cannot recover lost data.
Why are my iPhone photos in HEIC format?
Apple adopted HEIC because it stores photos at half the file size of JPG with equivalent quality. Use a HEIC to JPG converter to convert for sharing.
What is the difference between JPG and JPEG?
Nothing — they are identical formats. The three-letter extension exists because older Windows required three-character extensions.
Is WebP better than PNG?
For web use, usually yes — WebP lossless files are 26% smaller than PNG on average. PNG has broader compatibility for non-web use.
What is AVIF and should I use it?
AVIF is a next-gen format with better compression than WebP. Use it for high-traffic websites where every kilobyte matters.