Here's a little Javascript snippet I've been playing with to do this:
// Begin Variables
var str1 ="{image1}";
document.write(str1.replace("/home/MyAccount/public_html/URL.com/components/com_facileforms/uploads/", "http://URL.com/components/com_facileforms/uploads/"));
This is part of a PHP file I've been working on to preview uploaded images. I don't have it perfected yet, but I thought I'd try to help out.
Let me know if this helps. I can send the rest of the PHP file if you need it.