Yes, you can, but the form will have to be a script, not straight HTML.I was wondering if it is possible to return the variables into a new form page with a slightly altered lay-out.
You can convert your HTML page to PHP, for example, by renaming it from something.htm to something.php (assuming your webserver will serve PHP pages).
Then, in the bad_url setting, specify the original form (something.php).
FormMail will then call the bad_url target when the user has an error. It will pass the error details in the URL and also in the Session variables.
With some relatively simple PHP logic, you can easily modify the output of the form as you wish, to incorporate the error details.
I've made this sound simple, but you do need to be a bit of a programmer to get this done.
As to the alternative, if you use the bad_template feature with our fmbadhandler.php, it currently does not support the return link being an image. However, we can add that in a future version if you need to go that way.