It's people who review. Otherwise how can a computer say "This is not what we are looking for" in some cases. It has to be trained people who use specialized software to check for problems one by one. Maybe one guy specializes in JPEG artifacts and another in color? Maybe it is like a manufacturing line. Our photos go in past a number of reviewers who look at different aspects. And suppose the fourth one has the task of checking the composition and he finds it bad, he declines it and you automatically get a preset "bad composition" rejection. Of course, we can't expect them to type whole reasons. They have quite a few thousand photos a day.
55-250mm standard lenses. Dual tube macro flash and external speedlit...
Hi Alisonun, I'm one of Dreamstime's reviewers, and I'm a human, trust me :)
Actually, each photo submitted to Dreamstime gets to be seen at full size by at least one (human) reviewer. The rest of the review process cannot be publicly disclosed, but we're trying to fit the high standards demanded by our buyers.
Some of the refusal reasons are standard, some of them are custom written, depending on many factors.