You have to get the address of the uploaded image. The link you've got is the address of the page that shows the image. If you right-click on the picture itself, there should be a "Copy image location" or "properties" tab, eventually you should be able to find something like like http: //www.canreef.com / blah-blah-blah / blah-blah-blah.jpg. Copy that and put it in between [ img ] and [ /img ] tags. (Hope this helps..)
Anyhow though, those don't really look like sundial snails to me. They could be baby trochus. Here's a page that shows what sundials look like:
http://www.thesea.org/reef_aquarium/...sts_snails.php