Sometimes I remember how to put photos and such into the post, but more often, I just look it up in another post. Here's a cheater's tip to embed photos or links: when you forget how to do something, find a post in which this was done and click on the "quote" button. This will show you exactly what you need to do. You can then copy that text and either type or paste it into your post, substituting the information about your picture or link. People who program poorly, like me, do this all the time.
This works with other coding, too, like statistics (if you have to do the same operations with different data). My good programmer friends say this is not the best way to do things, but, like eating too many sweets and drinking and jaywalking, everybody does it.
You can also use the Img and URL buttons - click the button for what you want to embed (an image or a link), add the picture/link and title, and click the Img or URL button again.