Android 5.0 Lollipop has a feature which activates the screen of the Android device to show different images, colors, clock, or photos from albums when the device is not in use. This is, specifically, useful when the device is not in use, charging or docked. In addition to it, the display of clock on the screen may help some of the users to be aware of the time on the digital or analog clock, i.e. it can be used as the watch for the Android device users.
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You may activate the Daydream feature in few steps but you may also have help from the instruction, if need is felt. After activation, you may set different features in Daydream.
Instructions
Command Line: Settings – Home > Display – Settings > Daydream – Display > Daydream – ON/OFF.
1: Tap the icon of the ‘Settings’ app on the Home screen of your Android 5.0 Lollipop device to open up the ‘Settings’ screen. 
2: At the ‘Settings’ screen, scroll down to the ‘Device’ section and tap the ‘Display’. 
3: At the ‘Display’ screen, tap the ‘Daydream’. 
4: At the ‘Daydream’ screen, see the daydream is switched ‘Off’, as is indicated fade switch of Grey color. Here, Android also gives you message, “To control what happens when the phone is docked and / or sleeping, turn Daydream on.” 
5: Tap and drag the switch of the ‘Daydream’ to the right to switch ‘On’ it which is indicated by the change of color of switch from Grey color to Sky Blue color. In addition to it, 4 different options, along with their settings, will appear on the ‘Daydream’ screen after the activation of the ‘Daydream’. 
Now, you can select and choose any option to display as the daydream on your Android device when the device is either docked, charging or sleep.
That’s all!
I have a LG G2. The Lollipop “upgrade” is an absolute disaster. They removed everything from Daydream except “Alarm/Clock” and “Google Photos.” No more photo table or photo frame.