Google AdSense has said it's offering new richer text ads, which automatically changes text ads into image ads. The ads will be automatically set to on if you have display-only, or text and display set on your site. Disabling is easy, if you wish: Just go to the Enhanced display ads, which you'll find in Allow and block ads.

I'd be interested to know how this is going to work out for your earnings.

Today, we’re happy to introduce richer text ads, a new ad format that automatically creates image ads from text ads. The new richer text ads compete both for your text and display, and display-only ad units and could increase your earnings even more.

This new ad format, inspired by material design, adheres closely to the advertiser’s brand by using their logos and brand colors. This enables brand advertisers who are particularly sensitive to how their text advertisements are displayed to spend more on the Google Display Network, thereby increasing competition for the ad units on your site. Google AdSense New Richer Text Ads [adsense.blogspot.com]