Hi,
Our current setup does mean that it is much, much easier for someone to upload an unfree image than it is for someone to delete it. This makes sense when it comes to valuable freely-licensed content, but is not ideal when it comes to the "I found this image somewhere on the web and slapped a fair use template on it" images. But there are drawbacks to adding more hoops to jump through in the upload process, as pointed out by Gregory Maxwell and others here -- we don't want to make it any more difficult for people to contribute their original work.
Another technical solution might be to impose terrible resolution on unfree images, which itself could be switched off (perhaps by bureaucrats) when there is a real need to (as, for instance, with the Jyllands-Posten Muhammad cartoons). If the default was for unfree content to be less aesthetically appealing than freely-licensed content, we wouldn't have editors constantly replacing freely-licensed images with unfreely-licensed ones.
Incidentally,
I've always regarded our lack of photographers as a product of the greater startup time consumption (can't really take half a picture), combined with our culture which isn't that friendly to photographers.
An unfriendly culture? Hadn't noticed that myself.
At en we have proven largely willing to say to photographers that their work is not valued. We pay a kind of lip service to how great it is to have freely-licensed material, but it is regularly replaced by more professional-looking images found elsewhere on the web under a "fair use" claim. That would certainly suggest that doing photography for en is not worth one's time.
Jkelly