Role and entry point

A Photos editing extension brings another app’s tools into Photos as a macOS app extension. Install and launch an editor that offers one, open a picture in edit mode, and inspect the extensions menu. If it is absent, check both the app’s activation steps and System Settings.

Test while preserving originals

Begin with a duplicate or test image rather than an important original. After saving, check whether Photos can revert the edit and whether a separate file was created. RAW support, masks, and re-editing differ by app; verify required features in its current product documentation.

Scope of the expert source

Keir Thomas’s Macworld overview notes that Photos plugins may be bundled with standalone apps and require a first launch and approval before being enabled in extension settings. The article is from 2017, so use it as background on setup, not as a current product or compatibility list.

Work on a duplicate. In Photos, open the image and click Edit. Choose Extensions > Manage, then use the info button beside Photos Editing to enable the app. Return to Photos, click Done, then click Edit again to reopen the edit view. Choose the app from Extensions and make the adjustment. First save the photo in that app and close its window. When Photos shows the updated image, click Save Changes in Photos, then click Done to finish editing. To undo edits, choose Revert to Original in edit mode. Labels can vary by macOS version.

Separate iCloud sync from editable parameters

With iCloud Photos, edits made on one device can appear on other devices using the same Apple ID. That describes sync of the edited photo; it does not guarantee that the extension’s individual sliders or settings remain adjustable on another device. Check the app maker’s documentation for extension-specific re-editing and recovery behavior.

Sources