Canon EOS 80D Manual (en)

Moving an Overlay Image
An image displayed as an overlay (the overlay image) in the [Remote 
Live View window] can be moved to a new position. You can also use 
the cursor of your mouse to enlarge/reduce or rotate the image.
Click the [Move overlay image] button.
Drag the cursor of your mouse over the overlay 
The overlay image is moved to a new position.
You can drag the cursor of your mouse in the [Remove Live View 
window] in the area outside the overlay image to rotate it.
You can drag the cursor of your mouse in the corners of the 
overlay image to enlarge or reduce it. 
Clicking the [Reset] button resets the image to its default state.
Displaying a Different Overlay Image
An image displayed as an overlay (the overlay image) can be changed 
to another image. 
Click the [Open] button in [Overlay].
The [Open] dialog box appears.
Select the image you want to switch to in the [Open] 
dialog box and click the [Open] button.
The image that was displayed changes to the selected image.