Today I was observing whatsapp app behavior. By using camera I took a photo. That photo got stored in camera directory of my cell phone(obviously that is normal behavior). And after that I shared the same photo to one of my contacts using whats app. After sharing, I deleted that photo from camera directory and checked my whatsapp contact(to whom I shared the photo) it was still in the list of messages. Then I found over the google that whatsapp also stores sent images in internal directory as well. Then I deleted the same photo from whats app internal memory and checked whats app contact(to whom I shared photo), i found that there was not real photo but blurry image of the same photo was there (that is called thumbnail). I tried to find out from where it was getting that thumbnail? I searched my whole cell phone directory or even whatapp media directory as well but could not find the thumbnail. My question is what is the location in cell where whatspp stores the thumbnails? I am assuming that whats app keep thumbnail url and download on demand.Is that right? Any help?