LG G4 User Manual page 55

NOTE
While playing a video, slide the right side of the screen up or down to adjust
the sound.
While playing a video, slide the left side of the screen up or down to adjust
the brightness.
While playing a video, slide your finger from left to right (or vice versa) to
fast-forward and rewind.
Editing photos
Deleting photos/videos
Setting wallpaper
NOTE
Depending on the software installed, some file formats may not be
supported.
If the file size exceeds the available memory, an error can occur when you
open files.
Set image as
DELETE
Camera and Video