Knowing If a Flickr Photo Has Been Explored
There are ways to find out how popular a specific Flickr photo is, whether owned by you or someone else.
A first indication of popularity on Flickr is the view count. Go to the photo's individual page and scroll down. On the right hand side of the page, you will see the view count. This is the total number of unique computers that have viewed an image, so it does not increase when someone re-visits a photo.
Slightly above the view count, you will find the number of Flickr users who have added the photo in question to their favorites list. This is more an indication of an image's artistic impact than of its sheer imprsssion count, but you can extrapolate a lot from it also.
Slightly above this, notice whether the photo has been added to many groups. Most Flickr groups are open by invite only, and heavy group inclusion is a good indicator of popularity.
Flickr's Explore Function
Another indication of a photo's popularity is whether is has made in into Flickr's "explore" stream. Use this tool to determine whether it has.
If you are a Flickr pro member, you will also have access to photo statistics. On any Flickr page, select You > Your Stats to have a look at statistics and graphs related to photos on Flickr.Popular P&S Cameras for High Quality Photos: