I think it's quite saturated and the success depends on how well you can attract companies who already use some other stock.

Currently, the best-paying stock is Adobe. Getty isn't as bad as "new" Shutterstock but they also lowered their rates years ago. The same portfolio earns 52% at Shutterstock, 25% at Getty/iStock, 12% at Adobe, 6% at 123RF, 5% at four more small stocks.

On Shutterstock more than 50% of sales come from outside the US, so it doesn't seem like there's much room to grow globally. The problem with Shutterstock is being a public company with growth expectations while not diversifying whatsoever.