Convert PNG Images to JPG and Choose the Background Colour
Turn PNGs into far smaller JPG files, deciding what colour replaces any transparency.
About the PNG to JPG Converter
PNG stores images without losing data, which is excellent for graphics and terrible for file size when the picture is a photograph or a screenshot full of detail. Converting to JPG typically cuts the size by a large factor. This tool exposes two controls for that: a quality slider from 10 to 100, set at 90 by default, and a background colour picker that starts at white.
The colour picker exists because JPG has no alpha channel at all. Any transparent region in the source has to become something, and rather than silently defaulting to white the tool lets you choose — useful when a logo with a transparent surround is going onto a coloured page. Multiple PNGs can be converted in one run with the same settings, and the whole conversion is performed by the browser, so screenshots holding personal information do not pass through a conversion service on the way.
Key Features
- Pick the fill colour: A colour picker decides what replaces transparency, instead of forcing white on every file.
- Quality from 10 to 100: The slider defaults to 90, which keeps screenshots crisp while still cutting the file dramatically.
- Batch conversion: Convert a set of PNGs in one pass, with a ZIP offered when there is more than one result.
- Predictable naming: Each output keeps the original base name with a jpg extension, so files stay recognisable.
- Large size reduction: Detailed screenshots and photographs saved as PNG usually shrink by most of their original size.
How to Use the PNG to JPG Converter
- Add one or more PNG files.
- Set the quality slider — 90 suits text-heavy screenshots, lower is fine for photographs.
- Choose the background colour that should replace any transparent areas.
- Convert, then download the JPGs individually or as a ZIP.
How It Works
Conversion runs on the Canvas API with no external library. The PNG is decoded, a canvas is filled with your chosen colour, the image is drawn on top of that fill, and the result is encoded through canvas.toBlob as JPEG at the quality you set. Two limits follow. Transparency cannot be preserved in any form, so the fill is permanent in the output. And because JPEG is lossy, a screenshot containing small text will develop faint ringing around letters at lower quality settings — keep the slider high for anything with type on it.
When You Need It
A caseworker at an advice charity scans benefit award letters, and the scanner software saves them as PNG at several megabytes each. The case management system accepts JPG and enforces a size cap, so every document needs converting. Those letters carry a national insurance number and a household income, so a free conversion website is not a reasonable place to route them. Similar pressure appears when a contractor converts screenshots of invoices for an accounting portal.