Differentiating between users on a social network scales in difficulty with the amount of information. To quickly discern the difference between one person and another; or one piece of content from another, we use icons or pictures. Often this can be solved by choosing or uploading a photo as a profile picture, or using a thumbnail version of the content.
However, when neither of these are available, it’s difficult to tell content or users a part quickly.
Generate a placeholder image based upon the hash of the content or the ID of the user.
When you need a default image to quickly differentiate between two users or pieces of content.
This image should have high enough entropy to cover the elements that would be visible in a typical user’s social network (e.g., 1000 items).
Visual hash is a good default image picker.