Extension in Photo
Photo running with El Capitan is showing the photo extension as not enabled.
How do I enable it ?
Itunes-OTHER, Mac Lion OS X
The extensions must be provided with the 3rd party application in order of them to be used with Photos. Currently there are 7 apps that include extensions for use with Photos.
Also you need to purchase the apps from the App Store before it can be used with Photos.
Intensify
BeFunky Express
Tonality
Noiseless
Snapheal
Affinity Photo
FX Photo Studio CK*
*This app was purchased from the developer and installed its extensions without issue. So it's not positive that the apps must be purchase thru the App Store.