If you are looking for a good app for you OS X, well here one of the few external editing apps that can be considered for your OS X photos is called Infinite editors. This is available on the App Store of Mac and is said to be priced at $1, this app allows you to make all the necessary editing work that you would want to do through the Mac image editor, and does not require any import or export.
In order to use this app for your editing purposes, all you need to do is using OS X photos, just go ahead and choose the image that you want to open. On either side, you will see that there will be various options that would be available will all the enhancements that are offered and you can start using them in order to make the changes that you want. Not only does it launch them automatically, however these options are ready to use and once you have gone ahead and made all the edits that you want, you can just go ahead and save it.
If you look at the original version of the image when you open photos, you will see that the changes would appear even on that magically. This app is said to be really impressive and what is appreciated about it is the fact that apart from the added convenience, it is a very simple and users finely app. considering the fact that the price is just $1, this app is truly worth that investment that you would make.
What is all the more better is the fact that it is so user friendly, that even a non technical person can easily use it and make the changes that they want without having to worry about technicalities.