Added Functionality for Your iMac Photos
Although El Capitan’s Photos application contains the common image editing functions that most iMac owners will use most — such as cropping, rotating, and applying filters — amateur and professional photographers will find that Photos lacks the more powerful features available in applications like Apple’s Aperture and Adobe’s Photoshop and Photoshop Elements. When Photos was originally released, there was no way to add functionality to the application.
With the debut of El Capitan, Apple allows other third-party software developers to add features to Photos by using extensions. Extensions are common in the world of image editing applications, providing add-ons like advanced filters, textures, and borders to the editing tools that Photos already provides. Extensions can be purchased through the OS X App Store. To add extensions, load any photo in Edit mode; then click the button bearing three dots at the right side of the Editing pane and click Extensions.
Another “new” feature in Photos is actually the return of a familiar face. Photos once again allows you to enter location data for an image (also called geotagging). Today’s iOS devices — like the iPad and iPhone — can add location information automatically (as can many high-end digital cameras), but now you can manually add a location to an image.
With the desired photo in the viewer, click the Get Info button on the Photos toolbar and then click the Add a Location button. (Manually adding a location also comes in handy when that automatic-location information is downright wrong.)