Here is how to get a custom/home made picture on your panel
1: Click Menu > Leave > switch user > start new session
2: Login as root:
3: Click the picture of a house at the top in the toolbar
4: In the top bar/address bar/location, type/copy and paste: /usr/share/apps/kicker/ and hit return.
5: A folder will apear with many different folders in it, find wallpapers and right click on it
6: select Properties
7: Go to permissions tab and in the 3 drop down menus. select "Can View & Modify Content"
8: Hit ok and Click Menu > Leave > switch user > start new session | and go back into your personal user.
9: Click the house icon once your in your person user, and in the location bar, type /usr/share/apps/kicker/wallpapers/
10: Highlight one of the pictures in there and do ctrl + c. then do ctrl + v in the same window.
11: a message will come up saying that a file like this already exists, Just change the name of the file to something else, change it to whatever you like: for example: "My theme"
12: Once "My theme" is in that folder, right click and click open with > Gimp
13: Gimp will pop up, you can edit this picture however you like, remember to keep it the same size so it doesn't muck up your panel
14: When you are happy with your new picture, close that window, and right click on your panel (at the top of the screen by default) > select: "configure panels"
15: In the config box, on the left hand side, select Appearance. Near the bottom where it says panel background, click on the little green browse Icon next to the bar and selects your picture, hit apply and it should change