Transparency, kept
A logo exported to JPEG comes out on a white or black block. Kept as PNG and padded onto transparency, it stays a logo. The header of each file is read for an alpha channel, so a rule can be limited to the ones that have one.
Questions about resize PNG
Will transparency be kept?
Yes. PNG keeps the alpha channel, and Pad with None fills the rest of the box with transparency rather than white.
Why is my PNG still large?
PNG is lossless, so its size depends on the picture rather than a quality setting. For photographs, WebP or JPEG is far smaller; for logos and screenshots, PNG is often the right choice.
Can I resize only the PNGs that have transparency?
Yes. In Applies to, set Transparency to Has transparency; the header says which files have an alpha channel.
Is anything uploaded?
No. Every PNG is decoded and written on your device.
