I'd like an uploader that; uploads regulars files, will scale images down client side (JPEG, GIF, PNG), can upload and resize a bunch of photos in one go with some sort of progress indicator. Free software (as in freedom) preferred. If it spots a mobile browser or phone and does something plausible that would be brilliant. Needs to work in current browsers (that includes IE8 still — no really some people still use it), but otherwise latest stable Chrome, and Firefox (We have no issue with telling people to upgrade their browser if a newer version would work better AND is available for their platform). Drag and drop highly desirable but if it opens the appropriate (native) multi file select dialog box then we can survive without drag and drop.
Best candidate so far is "plupload" — doesn't appear to have a switch for setting upload resizing client side — but that looks fixable as long as all the images in one upload are the same size, which is probably acceptable for our purposes. "plupload" can fall back to all sorts of exotic backends, but that is fine, as long as if I have a modern browser it "works" without them. Fall back to something for IE8/IE9/IE10(?) is almost mandatory. We already fall back to a simple HTML form when the users despair of Java or we don't detect Java.
I've looked at: Uploadify (no resize of images), SWF-Uploader (dying), GWT-Uploader (seems to be revamped SWF-Uploader), Silverlight File Uploader (obvious issue here), ThinFile Upload (Java and demo died), Agile-Uploader (seems to lack love), FineUploader (No image resize), and some other less notable uploaders.