I am using FB3 and I have a table where each record has a picture and some picture are duplicated.

I think to separate pictures into a new table.

But I need a method (server side is better) to not duplicate pictures again.

First, I need to know if exists function as CHECKSUM (magical number or else) to determinate a number to each picture. If exists, maybe will be easy to deploy. 

Looking for new functions of FB3 in release notes, I dont find anything. There is a HASH function but only for string.

Any suggestions?