I do not have 30 seconds to loose with such issues, and those 30 seconds can turn into 3 or 30 minutes after they decide to change their JavaScript to obfuscate the image URL and prevent people from doing what you are doing (thus bypassing their ads and whatnot)...
For these, I apply my rule: "Life is too short to loose your time with total suckers".
Anyway, this stuff got nothing to do with the original topic of this thread, so let's close the discussion here. Thank you.