Once they are in these sites you can usually right click on the photo and find properties - copy the address (URL:) and then, in the body of the message you can click "Insert Image" (second icon in middle row) when you are at the spot you wish to place the photo, position the cursor between the [ img ] [ /img ] characters and hit paste. The URL should appear between the [ img ] [ /img ] boxes. Then check with Preview. If you like it you can then Post.