The photo signed by all 3 is certified by PSA:
PSA/DNA Certification Verification #E41522
It is the opinion of PSA/DNA Authentication Services that the signature(s) listed below is/are genuine. According to the Certification Database, this item is defined as follows:
Item: 8X10
Primary Subject: TED WILLIAMS, JOE DIMAGGIO AND MUHAMMAD ALI
Authentication Date: 01/26/2007
Result/Grade: Authentic
The DiMaggio does look weird on that photo but PSA backs it for whatever that is worth!
Peace, Mike