u can use widgets (which are infact html/javascript codes) which will enable 3rd party functionality to ur blog....
for making images as link... first upload a picture to any imagehosting website.. u will get the url for tht image... save it. now put a HTML page element and use this code:
<a href="your_desired_link" img src="the_link_that_you_just_saved"></a>
so now tht image will show up when the page is loaded and when the user clicks on it... he will be redirected to the link specified.
do u want more info?
visit my blog to figure it out: www.jal-infotech.blogspot.com
visit other ppls blogs and learn.. i m sure this will help a lot. i wud also recommend u to visit iMav's site. it is beingmanan.com .. aesthetically very good site.