Photoshop CS4 will not open certain file types after upgrading to El Capitan

Hello, ever since I upgraded to El Capitan many files I want to open in CS4 (usually when I am trying to import video frames to layers) will not open and are 'grey' and unclickable. For example when I go to load video frames to layers it will not allow me to select a .gif or even .mp4... this was never an issue in older versions of mac software and is very frustrating now! I've looked through PS preferences but that doesn't seem to be where the problem is.. perhaps something about the El Capitan Finder?

Please help, since this is very limiting to my PS capabilities.