Last Updated: 03.07.2021

Copy pasta from their help page, used for personal reference

General

Function	Shortcut
Move window	right click drag
Open menu	right click
Select images	left click/drag
Focus images	double left click
Zoom to pointer	scroll wheel
Pan Scene	scroll click drag

Pro Mode

Function	Shortcut
Align Bottom	Ctrl+Down
Align Left	Ctrl+Left
Align Right	Ctrl+Right
Align Top	Ctrl+Up
Always On Bottom	Ctrl+Shift+B
Always On Top	Ctrl+Shift+A
Arrange By Addition	Ctrl+Alt+A
Arrange By Name	Ctrl+Alt+N
Arrange Optimal	Ctrl+P
Close	Ctrl+X
Copy	Ctrl+C
Decrease Master Opacity	Ctrl+-
Distribute Horizontal	Ctrl+Alt+Shift+Up
Distribute Vertical	Ctrl+Alt+Shift+Down
Export All Images	Ctrl+Alt+I
Export Scene	Ctrl+E
Export Selected Images	Ctrl+Shift+I
Grayscale	Ctrl+Alt+G
Help	Ctrl+H
Increase Master Opacity	Ctrl++
Load Images	Ctrl+I
Load Most Recent	Ctrl+Shift+L
Load	Ctrl+L
Lock Canvas	Ctrl+R
Lock Window	Ctrl+W
Maximize	Ctrl+F
Minimize	Ctrl+M
New Scene	Ctrl+K
Normalize Height	Ctrl+Alt+Left
Normalize Scale	Ctrl+Alt+Down
Normalize Size	Ctrl+Alt+Up
Normalize Width	Ctrl+Alt+Right
Note	Ctrl+N
Open Source	Ctrl+Shift+O
Optimize Canvas	Ctrl+O
Overlay Selection	Ctrl+Y
Pack All And Optimize	Ctrl+Shift+P
Paste	Ctrl+V
Preset Custom1	Alt+4
Preset Custom2	Alt+5
Preset Custom3	Alt+6
Preset Custom4	Alt+7
Preset Dark	Alt+1
Preset Glass	Alt+3
Preset Light	Alt+2
Redo	Ctrl+Shift+Z
Relink Missing Images	Ctrl+Alt+Shift+R
Reset Camera Zoom	Ctrl+Shift+G
Reset Camera	Ctrl+G
Reset Cropping	Ctrl+Shift+C
Reset Transform	Ctrl+Shift+T
Resize To Selection	Ctrl+Shift+R
Save As	Ctrl+Shift+S
Save	Ctrl+S
Settings	Ctrl+U
Stack	Ctrl+Alt+S
Toggle Bilinear Sampling	Alt+T
Toggle Grayscale	Alt+G
Transparent To Mouse	Ctrl+T
Undo	Ctrl+Z