I think that while the full blown libs might support more image types, something like BeroPNG is a far better choice in order to avoid library dependencies, you're going to to be able to load 9x% of the PNGs you find using it and you're defining your own content usually.

There might be some differences in speed but it's negligable, only the most chuggy old iphones are going to show much difference between some native arm lib or arm compiled bero.