In AEM x.x.x version we have mechanism to check duplicate images being uploading in DAM which is supported by unique SHA1 value.This verification process is done during uploading of new Assets.
1. By enabling duplicate OSGI asset service
2. OOTB mechanism is the SHA1 value check.
Currently , other way of achieving similarity/ identical is by using Sensei which will be based on tags but this process is again done AFTER successful Asset upload and enabling of SMART tags to specific folders.
WHAT WE DO NOT HAVE
We do not have mechanism where a Author WHILE uploading can know if there is any similar / identical assets i.e. Assets which have been cropped or change in color shade etc. This should not be related to any property value check or SHA1 value instead check the pixels or any other parameter.
AUTHORING Challenges use case
In our current system we have thousands of pages with images of business leaders with different dimensions / cropped belonging to different departments.The challenge for AUTHORS is if any leader resigns then his/her photo needs to be updated for the corresponding pages which can only be done after uploading a new photo in DAM. There is no way they can identify the pages where this new photo matches and then take necessary actions. The only one way they can achieve is by enabling SMART tags to the folders and then do Asset Search which is again driven by Tags.With our traditional approach of managing sites this is not possible mostly.