About the PNG to JPG Converter
Screenshots come out of most operating systems as PNG, and a full desktop capture can easily reach four or five megabytes. Ticket systems, wikis and mail servers push back at that size. Re-encoding as JPEG at quality 85 typically brings the same picture down to a few hundred kilobytes, and on a photograph the difference is almost impossible to spot at normal viewing distance.
Transparency is the one thing that has to be resolved first. JPEG has no alpha channel, so every partly transparent pixel is composited onto the colour chosen under Flatten onto, defaulting to white. Rounded corners and drop shadows exported on a transparent canvas therefore acquire a visible background: pick the shade that matches wherever the image will sit.
Keep the PNG whenever the image is a diagram with thin lines, a logo, or anything containing small text, because JPEG blurs those edges and leaves a faint halo around dark strokes. For those cases the size win is smaller anyway. Use the Max width menu to downscale and compress in one pass, which usually saves more bytes than either step alone.
How to use
- Drop the PNG on the left, or paste a screenshot straight from the clipboard.
- Set the Quality value and, if the PNG had transparency, the background colour.
- Read the new size in the status line and download the JPG.
Common questions
- How much smaller will the JPG be?
- For a photographic PNG, usually five to twenty times smaller at quality 85. For flat graphics the saving is much less.
- Can I get transparency back afterwards?
- No. Once flattened, the background is part of the image. Keep the PNG if you may need transparency later.
- What is the highest quality I can pick?
- 100, though anything above 95 mostly adds bytes rather than visible detail.
- Does this change the pixel dimensions?
- Only if you choose a Max width. Otherwise the resolution is untouched.