I just try to see what changes i have done the last few weeks one of my pages to see why i had a drop on Google .
I just notice i put in many of my photos a link back on the Photos of Printerest ( when you click on a photo divert you on my home page ) .
Is possible Google see that as a spam ? repeat in a varius photos the same link ?
This is not a good practice as the different pictures land on your home page but if you change the pics and the landing pages or put that images on different blog post of the official page then that wl be more better strategy.
Check other backlinks as well on Google webmasters.
If you havent created them, just ask Google to deindex them from its database.
If you are planning to get backlinks from Pinterest, make sure your landing page is not your site’s home page but some other internal page.
Try to get more relevant links from related websites ( related to your niche).
Make sure that your content is also good and you are not copying it from somewhere else.