Image Compression Explained: JPG, PNG and WebP

Images are usually the heaviest assets on a website. Compressing them properly can cut load times in half without anyone noticing a quality drop. The decision is rarely "JPG vs PNG vs WebP" in isolation, it depends on what you are showing, where you are showing it, and which browsers your audience uses. This guide covers each format honestly, includes AVIF (the next-generation format MDN recommends), shows browser-support tradeoffs, and gives a practical decision matrix you can apply to any image on any project.

JPG (or JPEG): the photograph workhorse

Best for photographs and complex images with smooth gradients (skies, skin tones, blurred backgrounds). Uses lossy compression, it discards data to shrink file size. Quality settings between 70 and 85 are usually invisible to the human eye on typical web display sizes but reduce file size meaningfully versus a quality-100 baseline.

JPG does NOT support transparency. Save logos and icons as PNG or WebP instead.

JPG is the most universally supported format, every browser, every device, every editor since the 1990s reads it.

PNG: the graphics-and-transparency format

Best for logos, icons, screenshots, illustrations, and anything with transparency or text. Uses lossless compression, every pixel survives exactly as you saved it.

PNG files are larger than JPG for photographs (because they preserve every detail) but are necessary when:

• You need transparency (the alpha channel)
• The image has sharp edges, text, or solid colour fields where JPG compression artifacts (blocky "mosquito noise") would be visible
• You want a master version to compress later

PNG-8 (256 colours) is significantly smaller than PNG-24 (16M colours). Use PNG-8 for icons and simple graphics where 256 colours are enough.

WebP: the modern web default

A format developed by Google, supported by all major modern browsers. WebP supports both lossy compression (like JPG) and lossless compression (like PNG), plus transparency and animation in one format.

For typical web photos, WebP files are usually meaningfully smaller than JPG at equivalent visual quality. For graphics with transparency, lossless WebP is usually smaller than PNG.

WebP is now the default recommendation from Google web.dev and MDN for production web images.

Verify the exact compression ratio for your specific images by trying both formats in our Image Compressor, actual savings vary with image content (photos with lots of detail compress differently from flat-colour graphics).

AVIF: the next-generation format

AVIF (AV1 Image File Format) compresses even better than WebP for many image types and supports HDR, wide-gamut colour, and high bit depth. MDN currently recommends AVIF as the most efficient modern image format where browser support exists.

Browser support for AVIF is now broad on Chrome, Firefox, Edge, and Safari (after Safari 16+) but may be missing on some older mobile browsers and embedded webviews. The standard modern serving pattern uses the HTML "picture" element to list AVIF first, then WebP, then JPG or PNG, so each browser picks the best format it supports. The picture element wraps multiple "source" tags (one per format with the matching MIME type) plus a fallback "img" tag for older browsers.

Most static site generators and modern CMS plugins generate this picture-element fallback chain automatically. Verify what your specific stack outputs before assuming.

Browser support quick reference

For up-to-date browser-by-browser support, always check caniuse.com, the practical reality:

• JPG / PNG / GIF: universal, every browser since the 1990s
• WebP: supported on all major modern browsers (Chrome, Firefox, Safari 14+, Edge, Opera, Android, iOS Safari)
• AVIF: supported on Chrome, Firefox, Safari 16+, Edge, Opera. Verify older browsers if your audience skews older or in low-resource regions

For a Pakistani / Indian audience on mid-range Android phones, WebP is universally safe; AVIF is safe on recent flagships but verify based on your actual analytics data.

Format decision matrix

Why this matters for SEO and Core Web Vitals

Google ranks pages partly on Core Web Vitals (Largest Contentful Paint, First Contentful Paint). Image weight is the single biggest factor in LCP for most content sites. Switching from JPG to WebP, or from WebP to AVIF, often produces a measurable LCP improvement on photo-heavy pages.

For a Pakistani / Indian small business or freelancer running a portfolio or product site on shared hosting (limited bandwidth and storage), every percentage point of image weight saved is real money on the hosting bill plus better mobile performance for users on 3G / slow 4G connections.

When to use SVG instead

SVG (Scalable Vector Graphics) is not a raster format like JPG / PNG / WebP / AVIF, it is XML describing geometric shapes. SVG is ideal for:

• Logos that scale to any resolution without quality loss
• Icons (smaller, sharper, themable via CSS)
• Charts, diagrams, simple illustrations

SVG is not appropriate for photographs (which contain millions of pixel-level details that vectors cannot capture efficiently).

Common compression mistakes

• Saving PNG of a photograph: PNG keeps every pixel, for a 1920×1080 photo this can easily be 5-10 MB versus a 200-500 KB equivalent JPG. Always use JPG / WebP / AVIF for photos.
• Saving JPG of a logo with transparency: JPG does not support transparency, so the transparent area becomes white or black. Use PNG or WebP.
• Quality setting too aggressive: JPG at quality 30-40 produces visible blocky artifacts on smooth gradients. Quality 75-85 is the practical sweet spot for web.
• Re-encoding a JPG many times: each re-save loses more quality. Always keep an original PNG / TIFF master and export JPG / WebP from that.
• Forgetting to resize before compression: a 4000px-wide phone-camera photo on a 1200px-wide blog layout is wasted. Resize to the maximum display width first, then compress.

Try it yourself

Use our Image Compressor to compress JPG, PNG, WebP, and AVIF files right in your browser. Your images stay private since processing happens client-side, nothing is uploaded to a server.