OK, I'm not sure I understand the problem. Are you trying to get pictures from one place on your hard drive to another, or is the problem when you download something from the internet it won't let you, or it let's you download, but it goes to a different place every time?
If it's the third one the fix is easy. Click tools, then options, then the downloads tab in Firefox. You should see two choices, "ask me where to download" or "always download to folder" with a drop down box.
The next two sections on the tab let you alter the default settings on how download info is displayed and how various file types are dealt with.
