Maximum Unscaled Portrait Size?

[Blackfoot]

At what resolution are the portraits displayed?
The 'default' images are 63x63 so I have always assumed that was the maximum size before the image starts to get scaled... but I'm starting to wonder about that... prescaled images tend to look a little better than the ones FG scales on the fly... so I'm trying to scale to the images to the highest possible base resolution.
The 'Library' for 3.5 mentions 'It is recommended the size of the image be no more than 100 pixels in either dimension.' is that the max unscaled resolution?

[Trenloe]

Similar to the size of the player token, details in this thread: https://www.fantasygrounds.com/forums/showthread.php?t=17990

The Portrait size is constrained by \graphics\icons\portrait_mask.png and the frame being \graphics\icons\portrait.png

In the 3.5E ruleset portrait_mask.png is 63x63 - so images used for portraits will be scaled to this size to display in the top left of the FG desktop.