As a work-around I now use the Upload via E-Mail option. This is not as immediate as the direct upload, but is still quite quick. It does mean that your images firstly go to an 'E-mail Images' folder and you will probably need to transfer them from there to the intended destination - quite simple to do, really.
I have never had any problems uploading images when I go via the E-mail route.
Regards,
Ian Marr