To follow up my previous post about Symantec - I got good news.
Norton Antivirus does not block Image Uploader anymore. On the next day after Microsoft advisory release guys from Symantec removed Image Uploader from the stop list. I might post it earlier, but I decided to wait for a confirmation from Symantec officials.
So if anyone got users complaining about Norton Antivirus (or other Symantec apps) blocking Image Uploader, just tell them to get latest updates. It should resolve the issue.