Absolutely Asset Catalog is you answer, it removes the need to follow naming conventions when you are adding or updating your app icons.
Below are the steps to Migrating an App Icon Set or Launch Image Set From Apple:
1- In the project navigator, select your target.
2- Select the General pane, and scroll to the App Icons section.
3- Specify an image in the App Icon table by clicking the folder icon on the right side of the image row and selecting the image file in the dialog that appears.
4-Migrate the images in the App Icon table to an asset catalog by clicking the Use Asset Catalog button, selecting an asset catalog from the popup menu, and clicking the Migrate button.
Alternatively, you can create an empty app icon set by choosing Editor > New App Icon, and add images to the set by dragging them from the Finder or by choosing Editor > Import.