Problems with windows paths

[delphinis]

Now i changed the pathname by hand using

image_path = image_path.replace("\\", "/")

and i got the error

Error:
_tkinter.TclError: image "C:/SVN/Python/Trunk/Projects/PhotoViewer/OpenFolder.png" doesn't exist

but when i copy the exact string into windows file manager it opens the file without problem. So the path is correct..
I think that this is just a wrong error message...