networkliquidators - 2:06 pm on May 1, 2013 (gmt 0)
As a tip, your images being displayed in Google's universal search in the results, can offset your impression number. This is generally why impressions can fluctuate high in volume but receive no click-thrus.
Google Shopping also accounts in this number, which will also greatly increase impressions. Click-thrus for this traffic is low because the intent of the person may not be looking to buy vs. the rest of the user's intentions.