Much is made by some of the "lossless compression" claimed for some other foramts like png and tiff, but those just throw away a significant part of the original information the first time you save in that format,

Maybe there can be some information in some originals that some of these formats can't store? but as far as I know, png only uses deflate for compression. That (see see zlib here) is widely used for all sorts of applications and does not chuck bits away.