dropbox is a neat little software that let's you sync files from your local harddrive to an online storage, and back to as many PCs as you want. You can access those files from any PC with the client installed and also through a webinterface if you are on another machine.
You can also share files/folders with someone else (give them access with a key sent by email) and you have a public folder where you can upload stuff that anyone can access. There is also a Photos folder, where the webinterface displays them as neat little javscript galleries that you can instantly send to someone.
So, the next time you want to share a screenshot, you could simply move it to your dropbox folder, and link it in the forum within seconds. No imageshack or other crap required.
You'll get 2GB of online storage with a free account but you can choose to upgrade it with a monthly fee. I'm using the free version and I'm pretty happy with it (the 2GB are more than enough to sync my most important uni/work files, so I can always access them)
If you think it feels like I'm advertising for it, then yes, you're right. The reason is, that if someone signs up to dropbox with my referral link
https://www.getdropbox.com/referrals/NTQ5MDg4Nzk then me and the one that signs up get an additional 250MB of free storage.
So, I'm asking you, if you're even remotely interested in something like this, try it out using my referal. It's quickly installed and if you decide you don't like it, you can deinstall it just as quickly.
And even if you're not interested, do me the favor and sign up
edit: Don't use my referral code, I'm already at maximum storage. Use someone else's.