Looking at the pictures you posted I think you have a slow (sticky) first curtain because the exposed part of the picture is on top. If the pictures were taken with flash and using too high shutter speed the exposed part would be on the bottom. I believe there are 2 gears on the bottom of the camera that allows you to increase the spring tension on the shutter curtain. One is for the first curtain and one is for the second curtain. However, excercise the camera a lot might just cure it.