This article is primarily intended for less experienced users so that they have a comprehensive guide at their disposal. However, we hope that veteran users may also discover or rediscover a feature or trick that makes their lives a little easier.
In this options menu, you will also be able to choose a theme to personalize your Gmail page, as well as its wallpaper. It’s in that same menu, and when you click on it you can choose a theme from one of the wallpaper photos that Gmail offers you. If you want, you have a My photos button to choose a photo that you have on your computer.
Check also, How to Choose your inbox layout in Gmail