If you receive the message “Image editing is not possible without an Optimized Image or Original” when trying to edit a photo, this means the device you are currently using only has the Thumbnail version of the photo. Editing a photo in Mylio Photos requires an Optimized Image or Original-quality photo on the device you wish to edit on.
If Mylio Photos is running on another device on the same network, and that device has the Optimized or Original version, you can sync the higher-quality version to your device using the Actions menu. By enabling Sync on Demand this process will happen automatically.
If you'd prefer for your device to always store all of your Optimized images, adjust the Sync Policy.