I had this question after viewing How to load custom images in Access 2007 ribbon
I have already a customized ribbon but in search for the use of custom pictures I implemented the solution in this answer. I copy and paste both, the Ribbon XML in to the my Ribbon XML and also the VBA code in the module. I have given it, it's own module with the same name.
Working with ACCESS2010, my custom Ribbon stil works, but when I choose the added tab with the custom picture I get an error message.
"myDataBaseName can not execute callback function onGetImage"