I'm creating the covers from scratch. I'm looking at low res boxes and mimicking them. They aren't 100% replicas as I can't get the exact fonts and images. I can make harder to find covers. It just takes time. On one of the threads I posted, I displayed how I restore cover art and I used the Streets of Rage series as an example. No one has request F2 or Gun Nac from me so... I'm sorry, I didn't see your original question. I can help you.
Oh no worries, I hope I didn't sound pushy (reading through my post again I did sound kind of pushy, sorry!

).
Regarding screenshots, I can definitely put official ones together and slap them onto a cover. It's a tedious task, but one I'm fairly well-suited for since it really doesn't require any talent per se, just patience (patience I have, talent not so much

). There's a list of about 20 or so games I have for NES with boxes that are difficult to find and/or are extremely expensive so getting scans from them is quite cost prohibitive. Like I mentioned, Sneak has been working at getting the scans from various people on other forums, but there's no guarantee they will have all the games we lack. The rest of the games we're missing are easy and cheap to find so I just grab the boxes when I buy the games and make covers at that time, but if you'd be willing to help out making artwork for some of the harder ones, that would be fantastic!
Gun-Nac and F2 are at the very top of my list for this (and looking at mojo's post I'm not the only one

), and both have box arts available on GameFAQs:
Gun NacF2Obviously, these are too low-res to use as scans that would be suitable for covers, but if you could work your magic and recreate the artwork and just send me the blank template, I'll be more than happy to get the text and screenshots together. I don't know we'd be able to make it site-worthy, but I have no doubt they would be at the very least high-quality placeholders until (if ever) we can get good high-quality scans for them.
Also note that we DO have a version of F2 on the site, but as you can see it was done based off of the PAL version. Dunno if that would help with any artwork or not.
Thanks for any help you can provide!