feature request: it would be nice to be able to batch upload images and annotate them in one sitting

Essentially, it would be helpful if I were able to either create a folder and add images to it, or to simply upload a bunch of initial images and once I finish can move on to the next image by clicking a "next page" button or something similar. It would be neat to be able to download the group of images as a zip, as well as still download one by one. We should probably encourage regular downloading, given how MA's cache system works for memory (if someone accidentally refreshes or their browser updates, there goes your annotations), but it would be neat to batch download as well as upload, tho this might end up as a separate request/issue.