There are many posts about making the background image valid by making the "pills" green as a Dimension and continuous - Have done that with this example - still not valid.
There are references that if your data is outside of the X& Y axis range that it will be not Valid - As near as I can figure - they are not.
I am totally clueless as to what I can do next. I cannot find a single reference for any other issue that prevents me from having the image "valid".
Any hints are greatly appreciated.
Found a bug in the Tableau software 10.0.9. Not sure if it is corrected in newer versions.
The first image defaults to the Row and Column Axis inputs and nicely defaults to those values. But still states valid as no.
I added a second image that worked for me in the past, and then selected my 2 axis. - guess what - all of a sudden my second image worked, then I could switch to the first image and that worked.
See the ping file for what was done to make it work.