If I wanted to include a picture in my post, the first step (after finding the picture), is clicking on the icon that says "insert/edit image" (the one which looks like a tree, between the broken link of chain, and the goofy looking thing that is the content selector, its near the button for smilies), so I would click on the tree and get a dialog box to enter the url of a picture (I generally just copy that from the address bar) and then I might insert a description, and I might play with the alignment of the picture in relation to the text, I might also play with its size (when I play with the size I almost always keep the same ration of height and width) after that I would hit insert and be done with the picture.
I hope this clears it up for you.
Once you can tie your arms into a pretzel and your legs into a knot, you've got it under control