Setting Featured Image with code…

Hi guys,

I was wondering how difficult it would be to do the following…

I want to set up a forum so that all of my site users can enter data into. This data will be used to create a post that will have a featured image… is there a way to do this through code? I think I can do most of it, except I am not sure how I can get an image to upload properly (with all the resized versions and whatnot) and set this posts’ featured image through code

The only page I’ve really found with any information is https://codex.www.ads-software.com/Using_Image_and_File_Attachments, but it’s not really giving me any code…

Thanks,

–d