FLI vs FLC
"FLI" is the name given the original 320×200 resolution format that Autodesk
Animator creates. When Autodesk Animator came along with a resolution-indepen-
dent animation format, we needed to change the extension name to "FLC" so
applications could tell the two apart. Also, since Animator Pro was not an
upgrade but a parallel product to the original Animator, we didn't want
situations where users were trying to load a high-resolution flic into Animator
(which couldn't read it). This is also why 3ds automatically creates a "FLI"
file if you render to 320×200, and a "FLC" file in all other cases.
– Jack