Collapsed:
http://farm4.static.flickr.com/3218/2966682879_b618a9593c_o.png

Expanded:
http://farm4.static.flickr.com/3274/2966682919_0c1a5543f5_o.png

These images are Creative Commons licensed by Barry Schwartz. Here's the accompanying article:
<<Some AdWords ads on Google are now showing associated images — and getting much larger in the space they take up — through a “Show products from” Plus Box implementation that some are seeing now when searching at Google.>>
http://searchengineland.com/google-adwords-now-with-images-15242.php

One more click before clicking on the ads? I'm not sure advertizers will like it, because it will reduce click rate. What do you think?

I think it's even better for advertiser.

It seems like the first shown ad can still be clicked by users. But if someone wants to know more about the proposed offer, he then proves he's more "engaged" by expanding the ads box. Thus, he should be more likely to take action after having clicked on a "secondary" ad. As search ads are only CPC ads, it's seems to be quite a good deal, since here Google works to send "more engaged" potential buyer. The cost for big G would be the confusion in users' minds about its interface (K.I.S.S).