The syntax for embedding the link is there at the bottom of the cheat sheet. But first you have to put the image on the web somewhere. Personnaly i use my ‘‘blogger’’ account to upload my images to my blog (and to do this i use the app ‘‘bloggsy’’), then i copy the adress of the image from the blog page (i agree this is not very straight forward, i’ve seen some people tweet pictures, but i dont know how to do that).