Re: when I make an image ad why does the image size show up?
Are you referring to the physical dimensions of the image ads or the file size of the image ads? I would say either way, it's most likely to aide you in creating an ad that follows the standards for Display Ads. You can read more about the sizes here:
http://support.google.com/adwords/answer/1722096/?hl=en& (expand the sections on Specs)
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