If you dont have an image hosting site already, go to imgur.com and make a profile (all you need is an email, it only takes a few moments).
After you make an account, you can upload your pictures there. You will see the option to the right of the screen, it will open your files and you can choose the images you want to upload to the site.
After you upload them (it only takes a few seconds to do) just right click on the images you want to share, hit "open in new tab", open the tab that appeared, go to your picture and right click it again, and hit "copy image address".
Then, to use them here, just look at the little icons above the box you write your messages here in^. The last five on the right, the little speech bubble, the film icon, the picture with the tree, and the two blue orbs with the little staple (the one on the right being x'ed out), click on the little picture of the tree icon, paste the url that you copied from the picture in the tab you opened, and hit post. And the site will upload your pictures : p
