The inference was made from when you wrote "It'll also quit, but hey ...". So I assumed that you thought that the feature was unworthy.
Good suggestion but sorry it won't be good enough for other multi-image purposes. I'm not knocking the 'layer' feature at all, as I still use it a lot in my other image edits.
Also think about other instances where I would require a 'Save All' like for further example at times when I am editing 5-10 images that are each or some in different folder directories. Sometimes each image is of varying dimensions, file size or even transparency and I would like to maintain that when saving them to disk in a save all.
The 'save all' feature would simply do just that, with a single button/menu, and save all images without closing the entire program or the images opened itself. It's so useful on existing MDI applications like Notepad++ and Firefox. After clicking on a 'save all' then there should be an option to use or not use the 'save configuration' setting.
The only issue I just thought of on my feature request is when multiple images are opened without being saved for the first time (no file-type, just image on canvas). This is where it would get confusing because another option after hittin' 'save all' would be needed to be able to save all to the same or each individual image format. Maybe a forced 'saved configuration' window in this instance giving this extended capability. However, I am currently only interested in established image file formats that have been loaded into PDN. So for the aforementioned issue I just brought up, perhaps the 'save all' could be greyed out on that. Perhaps.