Why did I lose over a thousand pictures on my Samsung Galaxy Note4 phone?

[AC Question]

How can I get them back?

 

[Crashdamage]

Who knows? You haven't provided any information to help take a guess. Could be many things, from a bad SD card to operator error. But bottom line is you lost the photos because you failed to back them up.

As far as recovering the photos, if they were saved to internal storage see this:

http://forums.androidcentral.com/ht...contacts-after-factory-reset.html#post4657574

If they were saved to the SD card see this:

http://androidforums.com/index.php?posts/6903111