I found that yesterday. Once the template/etc. is all set up, you just upload to the FTP folder you have the images stored at, and it adds them for you.
I wonder how hard it would be to integrate that / have MODx gather X number of images as a "preview" for a specific album?
You could use a snippet to retrieve x amount of images for a preview. Look at the randomImage snippet for an idea of how to go about it. Also it seems that the code could be made into a snippet with not too much effort.
