How do I insert a custom field in a user submitted post?

I got custom fields working in the front end form linked in this post:

How to use nonce with front end submission form?

Here is the code used for the form page (custom page template): http://pastebin.com/YWyXL3jY

Hopefully that will be of help to you with a bit of tweaking to use image URL’s instead of text as the custom field input.

I had considered using the User Submitted Post plugin too but couldn’t figure out how to include custom fields with that, so ended up making the form by hand.