You could manually add them to var/[site name]/storage/original/application/ (I think it is the same directory as for binaries, but upload one and do a search for *.jpg or whatever your image extension is first) then create a reference in the ezimage table. I don't know if it'd work, but I doubt you'd cause serious damage if it didn't :)
Do you want a batch-upload-script for uploading lots of images to ez3?
Maybe have a look at this: http://ez.no/developer/ez_publish_3/contributions/image_batch_uploadscript_with_errors