I found http://www.plupload.com/ when I did look for a flash based upload tool which resizes images on the client side before uploading. It supports selection of multiple files, HTML5 and other browser plugins, so it's at least a nice toy.
It seems that the SBS video upload is already flash based to show a progress bar.
Any plans to add something like this to SBS?
This idea has been tossed around internally. Currently multiple file upload is not enabled, but have you tried using chrome + multiple images drag and dropped into the Jive text editor? That does work! Give it a try here in the Jive Community.