While I have about 1,000 images across 4 micro stock sites I am most passionate about Fotolia.com and since I see a lot of new users there having trouble getting files accepted and getting down right mad about it I thought I would explain a little bit about why it's getting harder and harder to get images accepted.
First off micro stock sites are fairly new to the industry and in the beginning there were not enough images to go around, stock sites need to have lots of images to attract buyers so in desperation they would accept most any half way descent image to build their library up.
Well the amateur photographers got the message that they could sell their images for money and they flocked to these site by the thousands. Pretty soon the sites were getting flooded with images and realized they needed to be a little more choosey.
After this it seems the flood of images was still getting bigger and they decided to start accepting only the cream of the crop so to speak. This would allow them to better their library and get more buyers. To the hobby photographer this seemed like the end as they could not get many pictures accepted.
Some saw it more as a challenge to hone their skills but most tend to see it as them against us when in reality if Fotolia (and other sites) can get a better library of images to offer then they will draw more customers and the photographers will sell more images. It's better for everybody all the way around.
However this also means that some people that lack talent may get left out. I am sorry but this is a good thing, not every person with a camera should be shooting photos for the advertising industry. Lets face it if a designer is looking for a photo and he has to wade through thousands of so-so photos to find the one great one he needs he will be less likely to come back.
In the end I think people that want to submit to stock sites need to either suck it up and hone their skills or leave it to those that will. If you are considering stock as a new source of income, please spend a few hours a week (yes I said it) looking through the top selling photos. Determine what subject matter sells and look at what the top sellers look like in quality. Then pick a subject and shoot until it looks as good or better than what you found in the top sales and submit it. If you can't get your images to look that great then maybe you should not consider getting into stock.
To see my Fotolia images go here: http://www.fotolia.com/p/199552