Convert PNG to JPG
Turn PNG pictures into JPG files for forms, email and photo services, and decide what transparent areas become. Your browser does the work on your device; the pictures are not uploaded to our servers.
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JPG, PNG, WebP, AVIF, GIF, BMP or SVG, up to 50 MB each. You can also drop images here.
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What this tool does
The tool writes PNG pictures as JPG files with the same width and height in pixels. JPG is preselected; the list shows the size of every new file, so you can compare it with the size of the PNG and see whether the conversion was worth it.
PNG can store transparent and half-transparent pixels, JPG cannot. Instead of silently turning those areas white or black, the tool lets you choose the colour they get. The page also reads WebP, AVIF, GIF, BMP, SVG and JPG files, in case your folder is mixed.
How to use it
- Choose the PNG files, or drop them on the marked area.
- Leave Convert to at JPG.
- Set the quality. 90 is preselected and suits photos; see the example below for screenshots.
- Under Background for transparent areas, keep White, press Black, or pick any colour, for example the colour of the page the picture will sit on.
- Start, then download single files from the list or all of them as one ZIP archive.
How transparent pixels get their colour
A JPG file stores three colour values per pixel and no opacity. The tool first fills the whole picture with the background colour and then draws the PNG on top with the normal source-over rule of the W3C Compositing and Blending specification: each colour channel becomes α × the pixel colour + (1 − α) × the background colour, where α is the opacity from 0 (transparent) to 1 (opaque).
A red pixel (255, 0, 0) at 50% opacity (α = 128 ÷ 255 ≈ 0.502) therefore becomes (255, 127, 127) on white and (128, 0, 0) on black. Fully transparent pixels take the background colour exactly; opaque pixels keep their own. Soft edges, such as smoothed text or shadows, blend into the background, which is why a background that matches the final page looks clean.
The picture is then compressed by the JPG encoder of your browser at the quality you set. JPG compression changes colours slightly, most at sharp edges. The result has no embedded colour profile and none of the metadata of the PNG, such as text chunks or the creation time.
Worked example
Three PNG files were converted in Chrome at quality 90. A camera photo of 3000 × 2002 pixels that had been saved as PNG was 8,389,053 bytes; as JPG it became 1,375,148 bytes, about 16% of the PNG. Safari, whose encoder works differently, gave about 1.8 MB for the same photo.
A screenshot of a page of this site, 1280 × 800 pixels and 74,197 bytes as PNG, became 77,884 bytes as JPG: larger, not smaller. At quality 80 it was 61,126 bytes and at 70 it was 52,087 bytes, with visible halos around the text. The same screenshot as WebP at quality 90 was 40,850 bytes.
The site icon, 512 × 512 pixels with transparent rounded corners (9,962 bytes), became 14,568 bytes on white and 13,409 bytes on black. With the teal of the icon itself (#0b5a6b) as background it became 10,110 bytes, and the rounded corners disappeared into a plain square.
When JPG is the better format
| Picture | Better format | Why |
|---|---|---|
| Photo saved as PNG | JPG | Several times smaller at quality 90 (six times in the example) with little visible change |
| Screenshot with text | Keep PNG, or WebP | Flat colours and sharp edges compress well without loss; JPG blurs them |
| Logo with transparency, for any background | Keep PNG | JPG fills the transparent areas with one colour |
| Logo for one known background colour | JPG with that background | The edges blend into the colour of the page |
| Form that accepts only JPG | JPG at quality 90 or more | Keeps the loss small; check the file size limit |
Common mistakes
- Converting a transparent logo with the default white background and placing it on a coloured page. The white box shows; pick the page colour instead.
- Converting screenshots to save space. As the example shows, the JPG can be larger than the PNG, and the text gets fuzzy edges.
- Expecting transparency back after converting the JPG to PNG again. The background colour is now part of the pixels.
- Renaming picture.png to picture.jpg. The content stays PNG; some forms detect that and refuse the file.
Frequently asked questions
- Does converting PNG to JPG reduce the quality?
- Yes, a little: JPG always compresses with loss, while PNG does not. At quality 90 the difference is rarely visible in photos. It shows first around sharp edges, such as text and thin lines.
- Can I convert PNG to JPG without losing quality?
- Not completely. Quality 100 keeps the loss smallest but makes large files. If the picture must stay exactly as it is, keep the PNG; the image compressor can make a PNG smaller while keeping the format.
- Why does the transparent background turn white or black?
- JPG cannot store transparency, so every converter has to put some colour there. This tool uses white unless you choose another colour. Programs that simply drop the opacity show the colour stored under the transparent pixels, which is often black.
- Why is my JPG larger than the PNG?
- PNG compresses large areas of one colour very well, and JPG gains little there. Screenshots, diagrams and icons are often smaller as PNG. Photos are nearly always much smaller as JPG.
- Are my PNG files uploaded for the conversion?
- No. Each PNG is decoded and written as JPG by your browser, in a background thread of this page. You can check this in the Network tab of the developer tools: converting a file sends no request that carries the picture. When advertising is enabled and permitted, the page also loads third-party advertising scripts; the privacy policy explains this.
Last updated: September 29, 2026