I need to create formula field that populate full URL of FullPhotoUrl in User object.Currently the value of FullPhotoURL is'/profilephoto/729n00000004DSL/F
' where I cannot use for my third party application.It required full url from http: .The full url that required is : https://mycompany--test.cs30.my.salesforce.com/profilephoto/729n00000004DSL/F'
The issue that I faced is I cannot use FullPhotoURL in formula field, it prompt 'invalid field' error.I think it is due to System field cannot be use in Formula field.
I am thinking about update it using trigger but User object is common object whereby it already have a lot of trigger plus I need to update the existing data to fire trigger .Is there any other way beside using trigger?