JPG vs PNG vs WebP: which format should you use?
Three formats cover almost every image on your devices. Picking the right one before you compress matters more than any compression setting — here is the short version, then the details.
| Use it for | Best pick | Why |
|---|---|---|
| Photos for uploads and sharing | JPG | Accepted everywhere; quality scales smoothly with file size. |
| Logos, screenshots, anything with transparency | PNG | Lossless and supports transparent backgrounds. |
| Images on your own website | WebP | Typically 25–35% smaller than JPG at similar quality. |
| iPhone photos | HEIC (convert for uploads) | Efficient, but many portals reject it. Convert to JPG when a form refuses it. |
JPG: the universal photograph format
JPG (or JPEG) has been the standard for photographs since the early 1990s. It is a lossy format: when saving, it discards detail your eye is least likely to miss. That trade is adjustable — higher quality settings keep more detail and produce larger files — and it is exactly the lever a compressor works. Every browser, every government portal, every application from 1995 onward opens a JPG. When a form says "photo" without qualification, JPG is the safe answer.
PNG: lossless pixels and transparency
PNG stores every pixel exactly, with no quality loss ever — and it supports an alpha channel, so parts of the image can be fully transparent. That makes it the right choice for logos, interface screenshots, and any graphic where crisp edges matter more than size. The cost is size: a 12-megapixel phone photo saved as PNG can easily be 8–15MB, several times the JPG of the same shot. PNG photos also compress poorly, because photographic noise defeats its lossless prediction algorithms.
WebP: the web's own format
WebP, developed by Google, supports both lossy and lossless compression and typically produces files 25–35% smaller than an equivalent JPG. All modern browsers render it, which is why it has become a favourite for websites. Its remaining weakness is compatibility with anything that is not a modern browser: many older intake systems, form processors, and desktop applications still refuse it. That is why WebP shines for serving images on your own site, while JPG remains the choice for uploading to other people's systems.
What happens when you compress each format
The compressor above accepts JPG, PNG, WebP, BMP, and HEIC input up to 50MB — and always outputs JPG, because that is the format every upload system accepts. For a PNG with transparency, that means transparent areas are flattened onto white (the page tells you this before you start). For WebP input, re-encoding to JPG costs a little of WebP's size advantage but buys universal acceptance. In every case the encoder tests several quality and resolution candidates and hands you the best result that fits your target, with a low/medium/high warning when the trade is aggressive.
Frequently asked questions
Is WebP better than JPG?
For the web, usually yes: WebP typically makes the same photo 25–35% smaller than a comparable JPG. But JPG remains the safest choice for uploads, because every system built in the last 30 years accepts it. When you need maximum compatibility, save as JPG.
Why does my PNG become a JPG when I compress it?
The compressor always outputs JPG because it is the most universally accepted format. PNG supports transparency, and JPG does not, so transparent areas are flattened onto a white background. The page discloses this before you compress.
Which format gives the smallest file?
For photographs, WebP generally wins, with JPG second and PNG a distant third because PNG stores every pixel losslessly. For screenshots and flat graphics, PNG is often smaller than a JPG at the same visual quality.
Does converting between formats lose quality?
Converting a lossy format (JPG, WebP) to another lossy format re-encodes the pixels and adds slight generational loss. The effect is small at high quality settings, but avoid repeated re-saving; always convert from the original file when you can.