PNG to JPG converter
Make lighter JPGs from PNG files, with a background color of your choice wherever the PNG was see-through.
- Processed on your device. Your photos are never uploaded. How we know
- Free, no sign-up, no watermark
Drop PNG images to convert to JPG
Drop files, paste with Ctrl+V, or choose them from your device.
PixWrench’s code runs on your device. We don’t receive your files, file names or their contents.
PixWrench’s code runs on your device. We don’t receive your files, file names or their contents. What happens to your files
How to convert PNG to JPG
PNG is the format of screenshots, diagrams and exported graphics. It is exact, which is lovely, and it is often huge when the picture is a photo, which is less lovely. JPG trades a little invisible detail for a much smaller file that every phone, inbox and upload form accepts.
Two things decide how good the JPG looks. The first is transparency: JPG has no alpha channel, so see-through pixels must be painted onto a solid color. The second is the quality setting, which matters far more for sharp text than for photographs. Both are explained below, with real measurements.
- 1
Drop in your PNGs
Add one screenshot or a pile of exports. Each file is identified by its bytes, so a PNG saved with the wrong extension still converts.
- 2
Pick a background and quality
Choose the color that should fill transparent areas, ideally the color of the page or slide the image will sit on. Keep quality at 90 for text, or lower it for photos.
- 3
Save the JPGs
Download files individually or as a single zip. The original PNGs on your device are left exactly as they were.
What this tool does
- Background color for transparent areas, white by default
- Quality slider, preset to 90
- Reads PNG, plus JPG, WebP, AVIF and HEIC
- Batch conversion with a zip of results
- Color profile kept in the JPG
- Metadata: remove everything, or just GPS
Worked example: a graphic vs a photo
We ran two PNGs through the same MozJPEG encoder this tool uses (in Node) to show when the switch pays off.
| Source PNG | PNG size | JPG, quality 90 |
|---|---|---|
| Our test photo saved as PNG, 1600 × 1200 | 1,222,810 bytes | 219,965 bytes (−82%) |
| Flat-color graphic, 640 × 480, 53.8% transparent | 3,484 bytes | 18,705 bytes on white (5.4× bigger) |
The photo shrank to under a fifth of its PNG size. The simple graphic did the opposite: its PNG was tiny because flat colors compress well without loss, and the JPG grew even at quality 75 (8,632 bytes). On black instead of white, the quality-90 JPG measured 17,260 bytes. Lesson: convert photos, think twice about logos and icons. (1 KB = 1,000 bytes.)
How the PNG gets flattened and compressed
The PNG is decoded in a Web Worker into red, green, blue and alpha values. Each pixel is then mixed with your background color in proportion to how opaque it is: a fully transparent pixel becomes pure background, a half-transparent shadow becomes a 50/50 blend, and solid pixels are untouched.
The flattened image goes to MozJPEG, an optimizing JPEG encoder compiled to WebAssembly. The quality number steers how coarsely it rounds away fine detail: higher means more detail and more bytes. The embedded color profile is written into the JPG so colors stay the same in color-managed apps.
Screenshots, text and the quality slider
JPG compression works on small blocks of pixels and is happiest with soft, natural texture. Crisp black text on white is its worst case: at low quality you get faint smudges around the letters. For a screenshot full of text, keep quality at 90 or above and zoom in before sending it on.
If the text still looks fuzzy, JPG may be the wrong destination. A lossless WebP made from the PNG is often smaller than the original, or you can reduce the PNG to 256 colors in the image compressor. Our comparison of image formats walks through which one suits which picture.
Choosing the right background color
Soft edges, drop shadows and anti-aliased text are partly transparent, so they blend with whatever color you pick. A logo flattened onto white will show a pale fringe if you later place it on a dark banner. Match the background to the final destination, and keep the original PNG if you might need the transparency again.
Good to know
- Transparency is gone for good in the JPG. Keep the PNG if the image might go onto a different background later.
- Flat graphics can get bigger. Logos, icons and charts often compress better as PNG, as the worked example shows.
- Every JPG save loses a little. Do your editing first and convert once at the end.
- Huge images are capped at 50 megapixels on desktop and 24 on phones; you’ll be offered a resize to 6000 px on the long side, or a skip.
What happens to your files
Processed on your device. Your photos are never uploaded. PixWrench’s code runs on your device. We don’t receive your files, file names or their contents.
The PNGs you add are read by this tab and converted by WebAssembly code on your device; the background color and quality are applied locally too. Nothing about the images is sent to PixWrench. Your chosen background and quality are remembered in local storage for next time, and nothing else is saved.
Related tools and guides
Questions people ask
What happens to the transparent parts of my PNG?
They are filled with the background color you choose, white unless you change it. Partly transparent pixels are blended with that color.
What quality should I use for screenshots?
Stay at 90 or higher when there is small text. For photos, 75 to 85 usually looks the same at normal viewing size and saves more space.
Why is my JPG bigger than the PNG?
Simple graphics with large flat areas compress extremely well as PNG. In our test, a 3,484-byte graphic became 18,705 bytes as a quality-90 JPG. Keep such images as PNG or try lossless WebP.
Can I convert a folder of PNGs at once?
Yes. Add as many as your device’s memory allows and download them together as a zip.
Will the JPG work everywhere?
JPG has been the everyday photo format of cameras and the web for decades, which is usually why people convert. If a site needs a specific size as well, the image resizer can fix the dimensions.
Sources and review
- MDN — Image file type and format guide (JPEG and PNG)
- W3C — PNG Specification (Third Edition): alpha channel
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