if for a highly secret reason you restrict to image only then of course $ is way down i give adwords-users the tip to bid on images very low - because i know that there are sufficient webmasters out there to limit adsense to image only and thus excluding the majority of the bidding crowd which in turn - without competition - leaves image advertisers the unique chance of getting lowest possible clicks down to a cent or 2 for a full adunit image on my ALL text_image site i love images - because i strictly use the 3 officially published successful formats and hence i get video ads on other highest paying and attractive image ads competing with text ads and pushing eCPM substantially UP but that is a topic that has been covered already and has to do with smart pricing or free competition restriction / filtering-restriction of bidding market by SOME webmasters absolutely free competition on high quality / high traffic sites always is best for $ - for all parties in volved