LG G3 not syncing with google photos in my galley although the feature is activate why ?

[manhal shinnawi1]

recently i purchase lg g3 instead of note 2 , with new version of android , android 5 lollipop . i am satisfied very to upgrade to lg . before i use galaxy devices more than 5 years . the only problem i faced at lg g3 is syncing between google photos and my gallery . in my gallery there is two options to select box and Dropbox .
There is no mention of anything Google account . anyone have a solution or trick to this issue please help us