What version of Hugo are you using (hugo version)?

$ hugo version
hugo v0.126.1+extended linux/amd64

Does this issue reproduce with the latest release?

Yes.

Report

The images.Padding function currently ignores the transparency setting when padding a PNG image. While the documentation does state 'conversion to WEBP is required to support transparency' (under Other recipes), I can't see a reason why PNG shouldn't be supported, given that it has an alpha channel. For the moment I have resorted to first converting the image to WEBP, then applying transparent padding, and then converting it back to PNG, but this does not feel like an elegant solution.