Check for File Exists on another website?

Here is the situation.  I have two websites.  One site contains nothing but image files.  This is a sub-domain of the main website.  The main website allows the user to search a database of information and displays that information.  I create a grid with a link to the file.  In my row_databound function, I want to check to see if that file exists on my other website.  If it doesn't I remove the link, otherwise I leaves a link to that file.
 
I was hoping that there was a way to verify that the LINK actually goes to a file that exists?  Is there a way to do this?
 
Thanks,
Cory 
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