FastStone Image Viewer: Edit Shortcuts

1. Rotate / Straighten Horizon:

Alt+F4

2. Settings (F12)

- Mouse Wheel : Zoom In / Out

- Arrow Keys: Next / Previous Image

3. Clone And Heel : Ctrl + Left Click

- https://www.youtube.com/watch?v=qTXdM-NMySY&t=8m40s

4: Histogram: Curve

https://www.youtube.com/watch?v=qTXdM-NMySY&t=5m20s

5. Curves Tutorial:

- Horizontal : shadow....midtone....highlights

- Vertical: Up = Lighten,. Down = Darken

- Contrast: more horizontal = less contrast ; more vertical = more contrast.

https://www.dpreview.com/forums/post/38119620