Usually when you run your application in your emulator, you may see the usual ic_launcher image as its icon. You can, of course change the icon of your application with the image you want. For that make these changes in the Manifest file.
Within application tag
Here, flower is an image with extension .png(You can use images with extension .jpg, .gif, .png, .bmp, or .webp)
This is how the icon looks in your emulator:
Check the icon of the application named Deepthi in the picture below.
I just thought of blogging about this as I was curious about how the usual icon is changed at the beginning. Hope this post was useful.