Upload it to your library (link on left) and then you can select it to be included in the post. Also please be kind and re-size it so that one doesn't need to scroll to view it. Once you are logged in and have a photo in your library, right below the box on your post where you enter the text for a post you will see buttons (Bold, Italics, Underline, Quote, Image, and one with a folder on it. You want to click on the one with the folder, then select the photo you want with your post.