The video and the images are displayed in a player like in the following figure.
At the bottom of the video and image player, a control bar is present. The control bar contains different controls if the source is online or offline, and if a video or an image is played.
Control bar - online
The control bar contains the elapsed time and the Setting 
button.
Control bar - offline video
The control bar contains controls to manage the playback of a movie (Stop
, Play
/Pause
, Step backward 
and Step forward 
buttons), the current and total time, and the Setting button.
Control bar - offline image
The control bar contains the Setting button.
Click on the Setting button on the right of the video control bar. The Zoom controls and the Brightness and Contrast sliders will be shown.
Click the Zoom in 
/ Zoom out 
buttons to zoom in and out the image.
Click the Move up 
/ Move down 
/ Move Left 
/ Move right 
button to move up / down / left / right the zoomed image.
Click the Reset zoom button 
to reset the image zoom.
Drag the brightness slider 
to adjust the brightness of the image.
Drag the contrast slider 
to adjust the contrast of the image.