I think when I was testing, I was constantly loading a spritesheet deep inside a folder structure of game assets and the repetitive navigating of folders made me think it would be a good idea to save the settings. But as you point out, it's not really something a normal user would be doing. Thanks for all your suggestions btw, I'll be updating the software accordingly.
Well, after posting this was actually thinking that it would be handy to have an option to save a 'default loading path' (which can be changed).
You might even be able to re-use the current mru (without the file+ext) but save it in another file, one which may hold even more save option in the near future as mentioned in an earlier post.
It would be nice to also add the current way of path loading when browsing for a source image (open last used folder) as an option, so the user can choose between 'last used folder' or his/her's default but changeable loading folder.