That's interesting about your experience with Postimage. ... when you drill down into an album ...
containing multiple images, and open one of them in the viewer, there's no scroll feature to page through the images in that file. This was the first such site I had seen, that didn't have that kind of feature in its viewer. There's no drag-and-drop functionality, to rearrange photos in an album, either, just sort by name or file date. ...