I'm not a technical guru, but nevertheless, I'll try to help by writing my opinion.
Definition of the problem:
I can agree that there are some topics where "posting" means adding 3 pictures and clicking submit (multiply with XY posts a day). If you allow 5 pictures... Well... I do not know how "heavy" is this post for example but thinking as a layman picture takes more memory than pure text. Right?
Solution:
Limit picture posting, not to 1 per post, someone can add 30 posts a day. I do not know is feasible but: limit the number of pictures that can be added from one account to (I don't know) 6 a week or 15 a month.
I say this because we are family here, but generally speaking (If you listen to Slipknot you know what I'm talking about) people = shit. There will always be someone who will go against the rules.
I'm STRONGLY against this:
About not keeping everything for an indefinite period of time. I rarely if ever go back and search for something from months ago, and I think a 3 month limit is reasonable.
When I'm talking about this, I have in mind "my" topic GIMP's that didn't survive which is encyclopedic type and if you remove all posts older than XY months - there is no point to post there anymore. Also, many good stories will be lost too.
The idea to users who post tons of pictures:
You can make a collage from your pictures (find an example in some of my posts on the topic GIMP's that didn't survive). This will consume some of your time but in this way, you can save a lot of space.
The question to the moderator:
What if we use only [.img][/img]? All pictures can be hosted somewhere else and just posted as this tag. So they will not be taking space on the server. Am I right? If this is feasible you can remove the attachment option.
I do not know what is your policy about this, so I'll just ask:
I know that all of this costs, so if things go really rough I would love to help. And I'm probably not the only one ready to do that. I live in a third-world country so I can't give much but I'm here.
This place mustn't die!