Here are keyboard shortcuts (hotkeys) you can use with PhotoFiltre:

CTRL+B     Stroke and fill
CTRL+H     Image size
MAJ+H     Canvas size
MAJ+CTRL+H     Crop image (if selection enabled)
CTRL+J     Show image properties
CTRL+K     Repeat the last filter (Filter menu)
CTRL+L     Show / Hide the tool pallet
CTRL+N     New image
CTRL+O     Open an image
CTRL+P     Print current image
CTRL+Q     Quit PhotoFiltre
CTRL+R     Revert the image with last saved version
CTRL+S     Save current image
SHIFT+CTRL+S     Save the image under a new name
CTRL+U     Duplicate the image currently being edited
CTRL+W     Close active image
CTRL+Y     Redo last action
CTRL+Z     Undo the last action
SHIFT+CTRL+Z     Fade last action

Tools
K     Pipette tool
L     Magic wand tool
M     Line tool
N     Fill tool
O     Spray tool
P     Paintbrush tool
Q     Advanced paintbrush tool
R     Blur tool
S     Smudge tool
T     Clone stamp tool
U     Scrolling tool

Cf. How to use PhotoFiltre | PhotoFiltre Masks | PhotoFiltre Main Page