I'm not too familiar with the older soon to be deprecated Selenium RC interface.
I think there's 2 mistakes
1) sel.open("/www.jatinjewellers.com/"); URL need to be complete with protocol.,
, that's probably why you're getting timed out on the page load.
2) the getAttribute I believe you need to first pass it a locator, suffixed with the @property you want to get. sel.getAttribute("css=img[some unique filtering property]@src");
Of course that test in itself isn't useful. You're just checking if a hard coded image location exists, which pretty much doesn't touch any web front end logic worth testing.