Format Guides8 min read·Updated April 16, 2026

Image Formats Explained — The Complete Guide for 2026

JPG, PNG, WebP, AVIF, HEIC, GIF, SVG — what's the difference? This guide explains every major image format, when to use each one, and how to convert between them.

Quick Reference Table

Here's the cheat sheet:

• JPG/JPEG — Photographs, web images. Lossy, small files, no transparency. Use for photos. • PNG — Screenshots, logos, graphics with transparency. Lossless, larger files. Use for crisp graphics. • WebP — Modern web images. Both lossy and lossless, transparency, animation. 25-35% smaller than JPG. Use for web. • AVIF — Next-gen web images. Best compression (50% smaller than JPG), transparency, HDR. Use for maximum performance. • HEIC — iPhone photos. Excellent compression, Apple ecosystem only. Convert to JPG/WebP for sharing. • GIF — Simple animations. Limited to 256 colors. Use for short animated clips. • SVG — Logos, icons, illustrations. Vector format, infinitely scalable. Use for graphics that need to scale. • TIFF — Professional print and photography. Lossless, very large files. Use for print production. • BMP — Legacy Windows format. Uncompressed, huge files. Avoid unless required by legacy software. • ICO — Favicons and Windows icons. Contains multiple sizes in one file.

Lossy vs Lossless — What It Means

Lossy formats (JPG, WebP lossy, AVIF lossy) discard some image data during compression. The discarded data is chosen to be visually unimportant — at high quality settings, you can't see the difference. The benefit: dramatically smaller files.

Lossless formats (PNG, TIFF, BMP, WebP lossless) preserve every pixel exactly. No data is lost, ever. The tradeoff: larger files.

For web use, lossy is almost always the right choice. For archival, editing, or print, lossless matters.

The Format Decision Tree

Ask yourself these questions:

1. Is it a photograph? → JPG (compatibility) or WebP/AVIF (performance) 2. Does it need transparency? → PNG (compatibility) or WebP/AVIF (performance) 3. Is it a logo or icon that needs to scale? → SVG 4. Is it a short animation? → GIF (compatibility) or WebP (performance) 5. Is it for print? → TIFF 6. Is it an iPhone photo you need to share? → Convert HEIC to JPG 7. Is it a favicon? → ICO or SVG

Which Format Is Best for SEO?

Google's position is clear: use modern formats. PageSpeed Insights specifically recommends:

1. AVIF (best compression) 2. WebP (excellent compression, widest support) 3. JPG (acceptable, but not optimal)

Using WebP or AVIF instead of JPG can directly improve your Core Web Vitals scores, which Google uses as a ranking signal. For image-heavy sites, this is one of the easiest SEO improvements available.