In the Picture Folder dialog box, a 'Reload picture' would be usefull.
It's common to edit loaded images, so this button would avoid to have to browse the same image (with 'Change' button)
The path to the picturefile needed to be stored in the project file. In files with hundreds of images that would increase the filesize recognizable (depending on the path length). In that case, I'm the one, who wants a cleanup button, too. :)
I agree with Fred. The .odcl project is designed to be portable and self contained.
As of OpenDCL 8.0 Alpha 10, there is a better solution to the underlying problem. The addition of picture folder API functions means that it is possible to update picture folder images programmatically via lisp. A simple lisp function can open the project, update any images, and save the project. This puts the picture folder reload logic (including any hard-coded paths and filenames), outside the project and outside the runtime experience.