Right. The foundImageName() function returns the name of the collection, with the idea that a collection represents a particular element on the screen and you want to know which element is present, not which exact representation of that element is showing.
For situations where you want to know the exact image that was found, the foundImageInfo() function can be used instead. It returns a property list that includes an imagePath property with the full path of the image file, so instead of foundImageName() you could do this:
or, to eliminate the file extension, you can use the short name of the file itself:
put short name of file foundImageInfo().ImagePath