The trusted hand requirement sounds quite reasonable to me. The fact is that there are people using the upload facility as storage space for their own personal junk and there just isn't enough room for it. People like that do NOT sign up and stick around for a month to load their stuff up - they see the opportunity and go for it on the spot. Just delaying it would probably cut the amount of junk in half at least. And if you add the requirememt for contributing to articles beforehand, well then that gets rid of even more of them!
When they gave users the ability to link to graphics in their diaries on the open diary site they made the requirement that you had had a diary for more than 30 days and/or made more than 30 entries into it, to prevent people starting new diaries just to upload pr0n pics to shock people... they took the requirement off again about six months later, but it had been there long enough that most people realised that they couldn't do that any more.