post feature image

Here is a forum post that discusses how to set it as the post thumbnail or feature image depending on how you customize the code.

http://www.gravityhelp.com/forums/topic/auto-setting-the-the_post_thumbnail?

Please note that when using the gform_post_submission hook if you call it like this:

add_filter("gform_post_submission", "set_post_thumbnail", 10, 2);

That applies that code to all of your forms. If you append the form id to the end of gform_post_submission like this:

add_filter("gform_post_submission_5", "set_post_thumbnail", 10, 2);

That will apply that custom code only to that form id, in this example it would be form id 5.

We do plan on making this a built in feature in a future release.

It's working for other users, all I can suggest is make sure you made the proper edits to the code. It isn't going to work as is, you have to customize it to suit your needs. You have to modify the code with your form id, etc. I'm not 100% sure how Headway's custom_functions.php works if it's the same as simply putting code in functions.php so you may need to discuss that with Headway support.