Finally I had success in tests. I like to clarify some issues that I found at implementation of your solution.
After give a name for image field in "CSS Class" attribute, I failed in access it by jquery. After a lot of tries and inspect code of html page, I found that the class name was gived to DIV, not for IMG tag. After see this I make a change in jquery and finaly works. I used this:
CSS Class attribute: imgCNH (give a name to field)