How to say “On the phone” （手机里 vs. 手机上） Prepositions are always a fun part to learn of a language. Right now, I'm running into the difficulty of trying to describe "On My Phone". I've heard people say "手机上“ but, after Baiduing I also know that you can say stuff like "手机里的照片“。 Could anyone give their opinion on which is more commonly used and/or any differences in usage? 

A similar question was asked Is it correct to say “在手机”？ here and the answer used “手机上” 

 我正在手机上玩游戏


Could this have been switched to 手机里?
手机上 describes the act is observed by something from outside of the cellphone through the screen. I guess most of the humanity will do this way.

手机里, in contrast, suggests something is really inside the phone, e.g. in memory, storage etc.

So, 手机里的照片 "pictures (stored) on the phone" and 手机上的照片 "pictures (found) on the phone" may indicate the same thing. But if you'd say 我在手机里玩游戏, I must assume you're a relative of Siri.