Return a Result from Image::resize

[alice-i-cecile]

Nit: It's probably out of scope for this PR, but setting the size when we don't have any data feels weird. I'd put this in the condition 🤔 (and comment that it does nothing when called with a self.data equal to None.

The best would probably to return an Error, so user can react, but as self.data is exposed the test can just exist in user space.

Originally posted by @Vrixyz in #19116 (comment)

[tychedelia]

As noted in #19380, we don't actually want to return an error as just updating the descriptor size is a valid operation.