General idea:
Many items (majority small images) are created on the canvas. The user can click on any item and move it. 
I need the user to know which item was last clicked, by showing (drawing) a border/change brightness/any method.. around that item.
Is there any Image/item options to help apply this idea.
For example this is your button-
B1 = Button(root, text = "Click me", command = clickme)
we can pass more parameters here such as--
highlightcolor=
The color to use for the highlight border when the button has focus. The default is system speciific. (highlightColor/HighlightColor)
and
highlightthickness=
The width of the highlight border. The default is system specific (usually one or two pixels). (highlightThickness/HighlightThickness)
...
OR
...
Whenever the button is clicked you must be specifying some action to do in a function. What you can do is you can tell that function to slight increase the thickness of border by above parameters. :)
highlight clicked items in tkinter canvas?