OS X can not view GIF
Continuing the question as I've saw several people ask this and no one gave a answer. some say use quicklook, sometimes that don't work.
This is the answer and You should have known about it already.
open "get Info" From what ever file you want, select "Open With" and select Quicktime player(It should be 7.6.6) But I don't know if it's available anymore from apple as there have been no UPDATES in a Decade. Quicktime should work up to 10.15. Once you change the how it opens into quicktime, finder previews should work. and Gifs should open in the quicktime player to view.
There has been no Word on what REPLACES Quicktime on the MAC, nor what other application or resources pickups after it. Pitiful. Guess media compatibility or resources to understand it is not important to Apple anymore.
Mac Pro, OS X 10.11