Has anyone used the "gen_image" front end function successfully?

[Reaxion]

I want to use "gen_image" because it looks like there is opportunity to insert extra code into the image tag. if you are using it, please paste in a complete loop where it is successfully working!

This is what I'm talking about:
http://wiki.magicfields.org/doku.php?id=front-end_functions_v20#ejemplo_7

Thanks!

[Reaxion]

Sorry, this is for MF2....