it is impossible to put pictures directly onto this site from your desktop. This is because the only way to put pictures on this site is by linking from another place online. So in order to post here you must first upload your image onto the net through some other source and then post an img link.
Provides free reliable web hosting and is a good site to use to upload your images then just compy the img link from there and post it here. It takes a while to figure out but once you get going it is easy, just dont give up till it works.