change logo at OAuth authorization window

Hi , yes you can change this logo.

1. Head over to the developer console and find your application. 
2. From the left-hand side of the screen, select App Gallery
3. Click the Submit My App button in the middle of the page
4. Finally, scroll down and upload an App Icon for the application
5. No need to actually submit the app to the gallery, just providing an icon here is enough.