I'm thinking about increasing the level of my open source contributions a bit. Instead of searching blindly until I stumble upon an issue that:
A) Piques my interest
B) I feel somewhat qualified to implement

I figured I'd check with the tildes community. Is there any Open Source software that you use that is missing a feature/capability? Can you give a brief description of it (bonus points for links to an issue tracker with an open ticket :))?

Can't of course promise anything will come of it, but if I do pick up your suggestion at least I'll give you a ping if I make any progress!

TLDR:

I need a website that let's signed in users vote on each others photos, and stores that data on who voted for what in a database.

Background

I run a facebook group of about 2,000 members. This group is designed for analog (any non-digital format) photographers to swap high quality artistic prints with each oter. The community was essentially dead and the admin wanted to throw in the towel so I took over. We've made progress, the group growth jumped by over 500% in the first month after I took over.

Right now trading prints doesn't work well. People make a post using the facebook selling format, and those who are interested comment with the image they'd like to trade for. The problem is that the posts get limited visibility due to facebook's algorithms, and stale posts hang around. All of this reduces over all activity, and the majority of posts don't end up in a trade.

My solution is to do a trade event with everyone participating at the same time. Since facebook doesn't lend itself to this I'd like to whip up a quick site for the event. My time is so limited these days I really don't have the capacity to build something from scratch, and the group certainly doesn't have any other developers to help out with it (it skews heavily on the older side).

I'd like to find an open source project that lets users sign in (sign in using facebook would be a bonus) and upload/vote on images. After the voting closes, I'll write code to pair everyone up in a way that optimizes for everyone getting to make a trade. If Alice votes for Bob's image, and Bob votes for Alice's image, they would get paired up to make the swap.

I feel okay writing the code to map out swaps, but I'm pretty terrible at web design and especially at front end design. I've looked across github, but I wanted to reach out and see if anyone could recommend something that I might of missed.

I don't expect to have 2,000 members participate, I think it may be as few as under 100, so hopefully I won't need to worry about scale.

Thanks in advance for the help!