When one first creates a new project, that dialog lets you point to some external .PNG file, and then when that dialog completes, it generates 4 different pixel-sizes of ima
Use the website mentioned in previous posts to create the icons:http://android-ui-utils.googlecode.com/hg/asset-studio/dist/index.html Unzip folder and Go into you file explorer on (windows or mac) find AndroidStudioProjects > "app name" > app > src > main (replace the web one here)> res (replace the rest with the one from the unzipped folder the you already downloaded)
*Close android studio so that you can make changes and when android studio is opened again the changes will appear