please read the guidelines properly when we talk about this issue, it all comes to Encouraging clicks so you have to abide by the rules such as * May not encourage users to click the Google ads by using phrases such as "click the ads," "support us," "visit these links," or other similar language * May not direct user attention to the ads via arrows or other graphical gimmicks * May not place misleading images alongside individual ads * May not promote sites displaying ads through unsolicited mass emails or unwanted advertisements on third-party websites * May not compensate users for viewing ads or performing searches or promise compensation to a third party for such behaviour * May not place misleading labels above Google ad units - for instance, ads may be labelled "Sponsored Links" but not "Favourite Sites" see the guidelines where i have made bold May not place misleading images alongside individual ads this is what google has to say about, so if you are putting images, it should not mislead the people, thats the guidelines its all about. now its up to the publisher whether to use image or not, will i meet the guidelines, is my content a quality and my image relevant to my article or news whatever, i mean whatever your image is? it should be not misleading images. anyway lets find out more on this, cause thats the most important placement to get high ctr.
That's why I recommend publishers contact Google directly and ask about their own particular setup, it may be allowed, it may be denied, but if you take the time to ask, they may recognize you as a publisher who is concerned and WANTS to stay within TOS/Policies and see that you aren't out there just to pull a fast one CTR-wise.