The easy and fast way is what RJ explained. The only downside is the limit on size.
If you want to post larger pics....open up an account at Photobucket (it's free). Store your pictures there. Then to get them to show up in a post, Photobucket has a link that shows the proper text to reference that picture...you point to the pick...aim down...copy the text for the image...paste that in your post....and it will show up when someone looks at the post.
The first time is a bit of trial and error....you will get the hang of it.....
Or just do whar RJ suggested....