Can someone secretly track all the photos and messages from one's phone to their's?

[Nande]

My friend told me that one can secretly track all photos and messages from one android device to another device or into someone else's email. But how is it possible? Is it possible only if the same applications are installed in both the devices? or only one device can install application and trap all photos from other's phone? please clear this doubt for me....one of my friend's mom kept tracking all her photos and messsages without the knowledge of her daughter...how would this be possible? and if its possible, please someone tell me which app makes this possible( please tell the name of the application so that i can be aware of its name)?

[?]

I can't say that I am very experienced in the field, however, with the right tools and technology, it can be done and with enough experience it can be done easily once the skills are acquired and practiced enough, so yes, it can be done.

The exact process, I am unfamiliar with.