Here is my final statement on the → launcher icon for Android
(as long as I don't get a contrary and convincing statement from the MIT team):
I recommend using an icon with the dimension 192x192px (in my case 78 KB) and uploading this to the media section (assets). If I use a 512x512 icon (0.6 MB) or 1024x1024 (1.3 MB), the same ic_laucher.png files are created as in the case of the 192x192 icon.
Note: But the original icon remains in the assets (1.3 MB in case of an icon with 1024x1024px and only 78 KB with an icon of 192x192px. So the AIA & APK are more than 1.2 MB smaller).
If I can (later) create an → iOS app, I'll replace this icon with a 1024x1024px icon.
For several good reasons, I am basically interested in the smallest possible AIA and (even more important) smallest APK.