Yesterday, Aditya asked me how to link a picture to a URL in the sidebar of Blogger. It's not possible unless the picture has already been linked by the hosting site. You can link from the post area. What you do is upload a picture, activate it by clicking to get the white boxes around the edges and then click link in the tool bar and insert the URL link. You can click on my son's picture as I have linked it to go to his blog. Try it out.