I admit my way is old fashioned, but I prefer to pause the game and pull out the old crayons and paper. This breaks the immersion of gameplay that I like, but when I've finished a drawing, I have a real feel of accomplishment.
My wife, however, thinks I'm a little too old to be taping my drawings to the refrigerator.

It's a bird... It's a plane... No, it is me :)

My input might not be of use to the OP anymore, but nevertheless: what about Dropbox? Not only does it create you a jpg instantly, but it also puts it in a public folder and you can just select its public link and post it wherever. Not to mention that you can also share pretty much anything else too. The free package includes 2 gigabytes of space, so you're not gonna run out of it too soon (and there are ways to get more free space with ease).

Looks like you`ve got some human stuck between your teeth, euww!!

Erm, what game is that?

Thanks for the info, kept a note of it for when/if I ever complete the current games I`ve to get through ;)