We are introducing JQuery to an existing ASP.NET application and use the Validate plugin for JQuery to do the client side validation (we do
Not sure if this will help, but give it a shot...
http://docs.jquery.com/Plugins/Validation/validate#options
$("input[type=image]").click(function() {
$($(this).parents(form)).validate();
});
You might need to replace the "form" with something more specific, but I tried to get it as accurate as possible without knowing how everything's laid out on your page. Reply if this helps!
The first suggestion might still work because you can cause the postback to fire using Javascript after the validation occurs.
The javascript is:
__doPostBack('<%= YourImageControl.UniqueID %>','');
The second empty parameter can be used to pass arguments.