I am looking for academic research that investigates how frequently Set as wallpaper and Delete functions are used in image viewer applications on mobile devices (to defend their inclusion in a list of essential features in a reduced feature set). I have tried searching on Google Scholar but haven't found anything. What resources/statistics are available for feature-related studies on mobile devices?
Circa 2008, Google Chrome had a much-discussed feature request over whether "Set as desktop background" should be in the context menu.
The issue was prioritized as
WontFix a year later, primarily to keep the browser lean and simple.
Comment 496 by email@example.com, Sep 30, 2010
Don't worry everyone, the reason why we implemented the extensions framework for Chrome is for features like this. Many people don't want that, while many people do. One of the three ideologies of Chrome is simplicity. And our objective is to make the browser simple, and let the user customize it.
Over the next few days, I will be implementing a Google Chrome extension that does exactly this, "Set as background".
The feature request link might help you make some decisions regarding your features. Lots of arguments for and against "Set as desktop background".