Need to release memory from unused images (Dispose?)

Question

Hello,

I am making a game, and want to unload images when they aren't needed.

For now I am just setting their sources to null:

 

imgExample.Source = null;

 

But this isn't enough.

 

I already tried Freezing, but it doesn't seem to help much.

 

I read that their is such thing like "Dispose()" that seem to unload all the memory, in such cases, but I don't know how to use it.

 

I tried:

 

imgExample.Dispose();

 

But it didn't work, it seems I am missing either some kind of variable, or a using directive.

 

What can be done in this situation?