Image formats explained: JPG vs PNG vs WebP vs AVIF

Lossy vs lossless: the one idea to understand first

Almost every choice between image formats comes down to a single distinction. Lossy formats permanently throw away some image data to make the file smaller — they exploit the fact that the human eye barely notices certain fine details. JPEG is the classic example: it can shrink a photo to a fraction of its original size while looking almost identical. The trade-off is that the discarded detail is gone for good, and re-saving a lossy file again and again slowly degrades it.

Lossless formats compress without discarding anything. Decompress the file and you get back exactly what went in, pixel for pixel. PNG and TIFF work this way. The upside is perfect fidelity and the ability to edit and re-save endlessly with no decay; the downside is that photographs, which are full of fine variation, produce very large lossless files. A rule of thumb: lossy for photographs, lossless for graphics with flat colours and sharp edges.

JPG (JPEG)

JPEG, saved as .jpg or .jpeg, is the workhorse of digital photography and has been since the 1990s. It's a lossy format tuned specifically for photographs and other images with smooth gradients of colour. At sensible quality settings it compresses a photo dramatically while keeping it looking natural, which is why almost every camera and phone saves photos as JPEG by default.

Its weaknesses are the flip side of its strengths. JPEG has no transparency, so it can't do see-through backgrounds. It struggles with sharp edges, text, and flat blocks of colour, where its compression leaves visible 'halo' or block artefacts. And because it's lossy, each re-save loses a little more. Use JPEG for photos you need to keep broadly compatible; avoid it for logos, screenshots, and line art.

Strengths: tiny photo files, universal support. Weaknesses: no transparency, artefacts on text and sharp edges, degrades on re-save.

PNG

PNG is the go-to lossless format for graphics. It stores every pixel exactly, so it's perfect for images with crisp edges and flat colour: logos, icons, screenshots, diagrams, and UI mockups all stay razor-sharp. Crucially, PNG supports full alpha transparency — smooth, variable see-through areas — which makes it the standard for anything that needs to sit cleanly on top of another background.

The catch is size. Because PNG never discards data, a photograph saved as PNG can be five to ten times larger than the same photo as JPEG, with no visible quality benefit. So the decision is simple: reach for PNG when you need transparency or a pixel-perfect graphic, and reach for something lossy when you're dealing with a photograph.

Strengths: lossless, full transparency, perfect for graphics and screenshots. Weaknesses: large files for photographs.

WebP

WebP is a modern format developed by Google to do the jobs of both JPEG and PNG, only smaller. It has two modes: a lossy mode that competes with JPEG and typically produces files 25–35% smaller at similar quality, and a lossless mode that competes with PNG. It also supports transparency and even animation, making it a genuine one-format replacement for the older pair in most web work.

Browser support is now effectively universal across current browsers, so serving WebP on a website is safe in practice. The main friction is outside the browser: some older desktop apps, email clients, and design tools still don't open WebP, so it's less convenient as a format for files you email around or hand to non-technical people. For the web, though, WebP is an easy win over JPEG and PNG.

Strengths: smaller than JPEG and PNG, transparency, animation, wide browser support. Weaknesses: patchier support in older desktop and design software.

AVIF

AVIF is the newest format in common use, based on the AV1 video codec. It's the compression champion: at the same visual quality it usually produces the smallest files of any format here, often noticeably smaller than WebP, and it handles both photographs and graphics well. It supports transparency and a wider range of colour and dynamic range than JPEG, which helps with modern high-quality displays.

All current major browsers now support AVIF, so it's a strong default for images on a fast, modern site. Two practical caveats: encoding an AVIF can be slower than encoding a JPEG or WebP, and support in older or niche software still lags. A common web strategy is to serve AVIF first and fall back to WebP or JPEG for anything that can't display it.

Strengths: smallest files, great quality, transparency, wide colour support. Weaknesses: slower to encode, weaker support in older non-browser tools.

GIF and TIFF, briefly

GIF is an old format limited to 256 colours per frame. That makes it a poor choice for photos, but it still shows up for simple, short animations and low-colour graphics. For anything more than a few colours or a short loop, a video format (MP4) or animated WebP will look better and weigh far less.

TIFF sits at the opposite end. It's a lossless, high-fidelity format built for print, scanning, and archival masters. TIFF files are large and rarely used on the web, but if a print shop or archive asks for one, it's because they want the full, uncompressed image with no quality loss.

Quick comparison

Which should you use? Practical recommendations

• Photographs on a website — AVIF first, with WebP or JPEG as a fallback. You get the smallest files and faster pages.

• Photographs to email or share widely — JPEG. It opens everywhere with no surprises.

• Logos, icons, and anything needing transparency — PNG, or WebP/AVIF if the destination supports them.

• Screenshots and diagrams with text — PNG keeps text crisp; a lossless WebP is a smaller alternative.

• Short animations — animated WebP, or a short MP4 for anything longer than a couple of seconds. Reach for GIF only when a tool specifically requires it.

• Print or archival masters — TIFF, when a printer or archive asks for it.

A note on quality and re-saving

Converting to a lossless format (PNG, TIFF) never degrades an image. Converting to a lossy one (JPEG, WebP, AVIF) re-encodes the pixels — a single high-quality conversion looks clean, but each additional lossy re-save compounds the damage. The practical habit: keep a lossless master (PNG or TIFF) of anything you'll edit repeatedly, and export a lossy copy only at the final step. When you do need to move a file from one format to another, a straightforward converter with sensible quality defaults does the job in one clean pass.

Convert between any of these formats

Ready to change a format? The free image converter handles JPEG, PNG, WebP, AVIF, GIF, TIFF, BMP and ICO — as both input and output. Drop your file, pick the target, and download the result. No signup, and files are auto-deleted right after conversion.