Once I edit a picture and flatten all the layers, how do I go back and re-edit the layers after I've saved and closed the picture? When I open the picture again I can't seem to find out how to get back in to view all the layers. Or is it even possible?
As American Horse posted, you can get back to the layered version using the history, but only if you have not closed it and reopned. Also, if you revert using the history, you also revert to a state before all changes made after flattening.
If you want to save a JPEG version but retain layers, just use "save as" and select JPEG. Then save the layered file as a PSD. The saved jpeg will look the same as if you had flattened evrything, and the PSD retains your layers (but, notably, not the history).
..that's why I like taking "snapshots", along the way. If I'm about to do anything radical, I just go to the history palette, and click on the little camera icon, at the bottom, and a copy of the current picture, with all its layers, is saved. Then, later on, even if I've flattened all layers, I can revert to any earlier snapshot taken along the way.
