About converting PNG to JPG
PNG stores every pixel losslessly, which is why photographs saved as PNG are often several times larger than they need to be. The lossy compression in JPG is built for photographic content - smooth gradients and continuous tone - and will typically cut the file to a fraction of its size with no difference you can see at normal viewing distance.
This is the conversion to reach for when a form rejects your upload for being too large, when an email attachment is bouncing, or when page-load weight matters. A gallery of photographic PNGs converted to JPG is usually the single biggest saving available on a slow page.
The trade-off is transparency. JPG has no alpha channel, so any transparent area is composited onto a solid background - white unless specified. Keep logos, icons and anything with a cut-out background as PNG, or convert them to WebP instead, which keeps transparency while still compressing hard.
Frequently asked questions
- Will converting PNG to JPG reduce quality?
- Slightly, by design. JPG discards detail the eye is least likely to notice in order to shrink the file. On photographs the difference is usually invisible at normal viewing sizes. On text, line art and sharp edges it is visible as faint halos, so those are better kept as PNG.
- What happens to transparency when I convert to JPG?
- It is lost. JPG has no alpha channel, so transparent pixels are filled with a solid colour, normally white. If you need both transparency and a small file, convert to WebP rather than JPG.
- How much smaller will the JPG be?
- For photographic images, commonly five to ten times smaller than the PNG. For flat graphics, logos and screenshots the saving is much smaller and PNG may even be the smaller of the two, since PNG compresses large areas of identical colour very efficiently.