Ultimate Guide to Image Formats: PNG, JPG, WebP, AVIF & More
A complete comparison of every major image format — PNG, JPG, WebP, AVIF, GIF, SVG, HEIC. When to use each, file size, quality, and browser support explained.
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Choosing the right image format can reduce your page load time by 40–60%, improve your Core Web Vitals score, and save significant storage costs at scale. Yet most people default to JPG or PNG for everything — missing out on substantial gains from modern formats. This guide explains every major format, its strengths and weaknesses, and gives you a practical decision framework.
Image Format Overview
Format quick reference
| Format | Compression | Transparency | Animation | Browser Support | Best For |
|---|---|---|---|---|---|
| JPG | Lossy | No | No | Universal | Photos, complex images |
| PNG | Lossless | Yes | No | Universal | Screenshots, logos, transparency |
| WebP | Both | Yes | Yes | 95%+ browsers | All web images — modern replacement for JPG/PNG |
| AVIF | Both | Yes | Yes | 85%+ browsers | Highest quality/size ratio |
| GIF | Lossless (256 colours) | Yes (1-bit) | Yes | Universal | Short animations (legacy) |
| SVG | Vector (no pixels) | Yes | Yes | Universal | Icons, logos, illustrations |
| HEIC | Lossy | Yes | Yes | Limited | iPhone photos (needs conversion for web) |
| BMP | None/lossless | Limited | No | Universal | Windows system use — avoid for web |
JPG/JPEG: The Web Standard
JPG (Joint Photographic Experts Group) has been the dominant photo format since the 1990s. It uses lossy compression that analyses each 8×8 pixel block independently — at high quality settings (85–95%), the compression is invisible to the human eye. At low quality settings (below 50%), artefacts appear as blocky smearing, particularly at sharp edges and areas of high contrast.
- Best for: photographs, product images, complex images with millions of colours
- Avoid for: screenshots, text-heavy images, images requiring transparency
- Quality setting: 75–85% is the sweet spot for web — visually lossless with 60–70% size reduction
- Does not support transparency — transparent areas appear white
- Multiple re-saves degrade quality — always keep a master PNG or TIFF
PNG: Lossless with Transparency
PNG (Portable Network Graphics) was designed as an open-source replacement for GIF, offering true lossless compression and full 24-bit transparency (alpha channel). Unlike JPG, PNG never degrades quality — you can save, edit, and re-save a PNG hundreds of times with identical output. The trade-off is larger file sizes for photographic content.
- Best for: screenshots, logos, icons, images with text, anything needing transparency
- Avoid for: photographs where transparency isn't needed — JPG or WebP is smaller
- PNG-8 supports up to 256 colours (like GIF); PNG-24 supports 16.7 million colours
- Full alpha channel transparency — unlike GIF's binary (on/off) transparency
- Excellent for source files — edit in PNG, export to WebP/JPG for delivery
WebP: Google's Modern Format
Developed by Google in 2010, WebP delivers 25–35% smaller file sizes than equivalent-quality JPG for photos and 25–45% smaller than PNG for graphics, while supporting transparency and lossless compression. Browser support reached 95%+ in 2022 when Apple added support in Safari 14. WebP should be your default web format for new projects.
Switch to WebP today
If you're still serving JPG/PNG on your website, converting to WebP can reduce total image payload by 30–40% with no visible quality difference. This directly improves your Largest Contentful Paint (LCP) score and page load times.
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Convert PNG or JPG images to WebP instantly — browser-based, no upload.
AVIF: The Next Generation
AVIF (AV1 Image File Format) is derived from the AV1 video codec developed by the Alliance for Open Media. It delivers 50% smaller file sizes than JPG and 20% smaller than WebP at equivalent visual quality. Browser support reached 85%+ in 2023. AVIF is particularly impressive for high-detail photographic content and images with gradients — where WebP can show slight banding, AVIF remains smooth.
GIF: Animation and Limitations
GIF (Graphics Interchange Format) is a 1987 format still widely used for short looping animations. Its core limitation is the 256-colour palette — photographs displayed as GIF look terrible. For new animated content, WebP or AVIF animation delivers significantly better quality at smaller file sizes. Use GIF only when you need maximum compatibility for simple animations.
SVG: Scalable Vector Graphics
SVG is not a raster format — it describes images as mathematical paths and shapes rather than pixels. This means SVG files look crisp at any size, from a 16×16 favicon to a full 4K display. SVG is the correct choice for logos, icons, illustrations, charts, and any image where infinite scalability matters. SVG files can also be styled and animated with CSS.
HEIC: iPhone Photos
HEIC (High Efficiency Image Container) is Apple's iPhone photo format, based on the HEVC codec. It achieves roughly 2× the compression of JPG at equivalent quality — an iPhone photo that would be 4 MB as JPG might be 2 MB as HEIC. The problem is limited web and non-Apple support. Always convert HEIC to JPG or WebP before sharing or uploading online.
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Convert iPhone HEIC photos to universal JPG format instantly.
How to Choose the Right Format
- Web photographs and product images → WebP (JPG as fallback)
- Icons, logos, screenshots → SVG (if vector) or WebP/PNG (if raster)
- Images requiring transparency → WebP or PNG
- Animations → WebP or GIF (GIF for maximum compatibility)
- High-quality next-gen web images → AVIF with WebP fallback
- iPhone photos → convert HEIC to WebP/JPG before sharing
- Source/master files → PNG or TIFF for lossless preservation
Frequently Asked Questions
What is the best image format for websites?
WebP is the best general-purpose format for websites in 2025 — it offers 25–35% smaller files than JPG with equivalent quality and supports transparency. Use AVIF for cutting-edge performance on modern browsers, with WebP as a fallback. Keep JPG/PNG only where WebP isn't supported.
What's the difference between lossy and lossless compression?
Lossy compression permanently discards image data to reduce file size — each save slightly degrades quality. Lossless compression reorganises data more efficiently without discarding anything — the output is pixel-identical to the input. JPG is always lossy; PNG and WebP support both modes.
Can I convert any image format to any other?
Yes, with appropriate tools. Our image converter supports conversions between JPG, PNG, WebP, AVIF, SVG, GIF, BMP, and HEIC. Note that converting from a lossy format (JPG) to lossless (PNG) does not recover lost data — PNG simply stores the already-compressed JPG pixels without further loss.
Why do my PNG screenshots look bigger than JPG photos?
PNG is lossless and stores every pixel exactly, including the sharp high-contrast edges in screenshots. JPG's lossy compression is inefficient on these flat-colour areas. For screenshots and UI captures, PNG is the right choice — but a WebP screenshot is typically 40–60% smaller than the same PNG screenshot.
Is AVIF widely supported enough to use?
As of 2025, AVIF is supported by Chrome, Firefox, Edge, and Safari (15.4+), covering approximately 90% of browsers. Implement AVIF with a <picture> element providing WebP and JPG fallbacks to cover the remaining 10%.