PNG or JPG: choosing a format for transparency and photographs
Choose between PNG and JPEG by checking transparency, sharp edges, file size and the needs of the destination.
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Choose for the image and its destination
JPEG is commonly useful for photographs where smaller files matter and some loss of detail is acceptable. PNG is useful for sharp graphics and images needing transparency. Neither format is always the smaller choice; the content and export settings matter.
Start by checking the destination's accepted file types, dimensions and file-size limit. A perfectly exported PNG is not useful when a submission form accepts only JPEG.
Handle transparency before converting
JPEG does not support an alpha channel. When you convert a transparent PNG, the transparent areas must become a background colour. Review that colour, especially around semi-transparent edges such as shadows or antialiased lettering.
For a logo intended for both light and dark pages, keep the transparent source. Export a JPEG copy only for the destination that requires it, and inspect it against the intended background.
Conversion cannot recover missing detail
Saving a JPEG as PNG does not undo JPEG compression. Blocks or halos already present in the source remain part of the image. Repeatedly editing and saving JPEG copies can introduce further losses, so work from the best source you have.
Use PNG to JPG or JPG to PNG for the required format change, then compare the result at normal viewing size and enlarged around text and high-contrast edges. Check the exported dimensions as well as the file extension.
Check size after quality
A large photograph saved as PNG can be much larger than its JPEG version. Reducing dimensions with Image Resizer may have more effect than merely changing the format. Keep enough pixels for the intended display or print size.
Try compression on a copy and compare the download with the original. Keep a version with readable small text and clean edges, even if it is slightly larger. Avoid using a file-size reduction as the only measure of success.
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