Add extra fiels to image edit form?

I want to add extra fields like “size width” “size height” “medium” etc for an artist website where the artist can change this information that’s associated with a particular image.

a) I’m not sure how to add these extra fields, I tried looking for a hook

b) on a side note, I also need to paginate the results and not just show one long page (as is the default by using the gallery shortcode)

I know there’s plugins out there like NexGen, but I would rather roll my own. Any suggestions?

Thanks!