Here's some examples of shedding. It's normal for turtles to shed some skin. They will shed more heavily when temps or warm or when they are fed rich diets. Excessive shedding is an indication of a skin infection or vitamin deficiency.
Light to moderate skin shedding:
http://www.redearslider.com/forum/viewt ... %2A#137696
http://www.redearslider.com/forum/viewtopic.php?t=15453
Abnormally heavy skin shedding:
http://www.redearslider.com/forum/viewtopic.php?t=14653
Here are examples of pyramiding and scutes ready to shed. Pyramiding gives a shell a lumpy look - the individual scutes display a somewhat pyramidal shape. When scutes have been retained, you can often see the layers of smaller older scutes then the newer bigger scutes, all stuck together. When scutes are close to shedding, you can see some lifting at the edges and they get a dull, sometimes whitish look. When scutes shed, only the top, very thin layer comes off. Don't "help" with the shedding, let the scutes fall off on their own.
Scutes ready to shed:
http://www.redearslider.com/forum/viewtopic.php?t=14952
Retained scutes:
http://www.redearslider.com/forum/viewtopic.php?t=16520
Pyramiding:
http://www.redearslider.com/forum/viewtopic.php?t=15940
In the example of pyramiding, there is also a photo of a turtle with metabolic bone disease, which is a very serious often fatal shell and bone condition caused by insuffient calcium and UVB light.