How can I undo changes?

[ximenaaaaaaaaa]

I wanted to try and change the picture for my classes on the dashboard, but I can't restore them to what they were originally.

[ksucpea]

What do you mean by originally? Like the image that was set by your teacher? If you put no value into the image it should remove any existing one (you might have to refresh the page for this to take affect though). If you put none it will remove any images, even the one your teacher set.