Note that the manifest simply refers to @drawable/ic_launcher, telling Android to
find a drawable resource named ic_launcher. The resource reference does not
indicate the file type of the resource — there is no .png in the resource identifier.
This means you cannot have ic_launcher.png and ic_launcher.jpg in the same
project, as they would both be identified by the same identifier. You will need to
keep the “base name” (filename sans extension) distinct for all of your images