Why does the approve pictures process take so long to load?

Sometimes (a lot of the time) it can take 15 to 30 seconds for a picture to load and display. When it takes that long I assume there are no more pictures to approve. And then one will show up. There should be a way to tell that there are no more pictures or that there are pictures. Sometimes after waiting for a long time I hit the Home button and then it will say that there are no more pictures to approve. Gets a little frustrating. Thanks...