Import support for more image formats?

[ElbertCode]

I recently wanted to import a .heif image into Rnote and found out that it didn't work. This wasn't much of a problem since I just converted it to a PNG and everything worked fine. But it made me curious so I tested which formats work and which don't (I just took a photo and exported it to various formats with Gimp), so I came up with this list:

Formats that work	Formats that don't work
PNG	BMP
JPEG	HEIF
GIF	TIFF
WebP	PNM
	ICO

I know that some of them (like .ico) make no sense for Rnote, these are just the formats I tested for fun.

I made a bit of research and found out, that the Rust image crate, which Rnote is using from how I understand the code (see /rnote-engine/src/render.rs in line 3), supports all of the formats I mentioned. So I wonder why Rnote supports some of them but not all? Is there a problem elsewhere with the other formats? Please note that I'm a beginner in programming and have very little experience in Rust at all, so it's very likely that I missed something.