Don't disagree with that at all. The structure is fine/good. The problem is that it is not nearly obvious enough. It has clearly confused many others apart from me (and I am pretty tech savvy). I had to spend ages physically moving files across to the correct folder via FTP without noticing the dropdown.
It's also not at all clear from the manual either
www.limesurvey.org/manual/Resources
Even more confusing in that it in fact shows the exact opposite - the image in the manual shows two image files (.jpg and .png) files in the "files" section.
Regular users will eventually notice the dropdown, but I think it would be worth an explicit message to the effect that file types should be uploaded separately via the dropdown, and that images are not files (which they clearly are). Another option is to make the default location images rather than files, and to pre-create an images folder so that this folder shows