JPG vs PNG vs WebP vs AVIF: Which Format to Use?
Every image you save has a format, and the choice changes how big the file is, how sharp it looks, whether it can be transparent, and whether the person you send it to can open it. This guide explains the four formats you'll meet most often and gives you a simple way to choose.
The two ideas that explain everything
Lossy vs lossless. A lossy format makes files small by permanently discarding detail your eyes are unlikely to miss. A lossless format keeps every pixel exactly, so files are larger. Lossy suits photographs; lossless suits sharp-edged graphics, text and anything you'll edit again.
Transparency. Some formats can have see-through areas (a logo that sits on any background); others always have a solid background.
JPG (JPEG)
The oldest and most universal photo format, from the early 1990s. It is lossy, has no transparency, and is understood by essentially every device, website, printer and app.
- Best for: photographs, email attachments, uploads to forms and anywhere that "just has to open".
- Watch out for: every time you open and re-save a JPG, a little more detail is lost. Edit from the original, and save the final version once.
PNG
A lossless format with full transparency. Edges stay perfectly crisp, which makes it ideal for screenshots, logos, icons, diagrams and anything containing text.
- Best for: screenshots, logos, graphics with flat colours, images with transparent areas, and files you'll keep editing.
- Watch out for: photographs saved as PNG are usually several times larger than the same photo as JPG, with no visible benefit.
WebP
A newer format from Google that can be lossy or lossless, supports transparency and can even be animated. Compared with JPG and PNG it usually makes files noticeably smaller — commonly in the region of a quarter to a third smaller than a JPG of similar visible quality, though results vary by image.
- Best for: images on websites, where smaller files mean faster pages.
- Watch out for: every modern browser opens WebP, but some older editing programs, office software and printers don't. If a WebP won't open somewhere, converting it to JPG or PNG fixes it.
AVIF
The newest of the four, built on the same technology as modern video compression. It can produce even smaller files than WebP at the same visible quality — often a third to a half smaller than JPG — and supports transparency and a wider range of colours.
- Best for: web images where every kilobyte counts.
- Watch out for: it takes longer to create, and support in older software is patchier than WebP. Treat it as a web format rather than something to email.
Side by side
| Format | Compression | Transparency | Best for | Opens everywhere? |
|---|---|---|---|---|
| JPG | Lossy | No | Photos, forms, email | Yes — the safest choice |
| PNG | Lossless | Yes | Screenshots, logos, graphics | Yes |
| WebP | Lossy or lossless | Yes | Web images | All modern browsers; some older software no |
| AVIF | Lossy or lossless | Yes | Web images, smallest files | Modern browsers; patchier elsewhere |
A simple way to choose
- Sending it to a person, a form, a printer or an app you don't control? Use JPG for photos and PNG for graphics.
- Putting it on your own website? Use WebP (or AVIF) for the smallest files, and keep a JPG or PNG original.
- Need a transparent background? PNG, or WebP if file size matters.
- Archiving or editing? Keep a lossless master (PNG, or the original from the camera) and make smaller copies from it.
Common mistakes
- Converting a JPG to PNG to "improve quality". It can't. The detail JPG discarded is gone. You just get a bigger file.
- Saving photos as PNG. Huge files for no gain.
- Re-saving the same JPG again and again. Quality drops each time. Always start from the original.
- Enlarging a small image. Stretching can't add detail. (If you really need more resolution, an AI tool such as the AI Image Upscaler rebuilds detail rather than stretching pixels.)
- Forgetting about iPhone photos. They are often HEIC, which many Windows programs can't open — see our HEIC explainer.
How to convert and shrink
You can change a picture's format with the file converter, set exact pixel dimensions with Resize Image, and hit a precise file size with the Image Compressor, which can also output to WebP. All of these run in your browser, so your images aren't uploaded.
Convert an image to another format in a few clicks.
Open the converter →