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I doubt you need to worry about the request for the javascript file, since after it is requested once, it is cached on the client computer. Subsequent requests by that user will not cause the server to resend the file. (It will log the request, but, not transmit it).
It can be advantageous to avoid using images when possible. However, image files cache, too. So, if you create a design that reuses the same small image, the file only needs to be sent to the user once.
However, let me see if I can find more about the stats, to help you with your quest.