Phone enters some weird Demo mode when locked

[romovs]

Ocassionly, when the screen is locked, strange pictures would appear on screen along with the following text near the bottom of the phone (writing from memory, so might not be exact) "Double tap a sample photo to exit the demo mode..."

What is it? And how can it be disabled? I couldn't find anything in setting.

P.S. I've enabled Developer Options. There is a setting called "Demo Mode", but it's switched off.

Other than that, found a pre-installed app "Retail Demo". But it cannot be unistalled.

[NunoSEN2]

@romovs;

What firmware Costumization Version do you have? (You can check it in the service menu dialing *#*#7378423# *#*) 

[romovs · Accepted solution]

The culprit is "Photo Playback" located in Ambient Display settings. All good now.