Palette requantisation from RGB to 256 colors:

ptime gconvert 20240826_074420G.jpg 20240826_074420G.gif
Aptime 1.0 for Win32, Freeware - http://www.pc-tools.net/ Copyright(C) 2002, Jem Berkes <jberkes@pc-tools.net> === 
gconvert 20240826_074420G.jpg 20240826_074420G.gif ===
<<< GCONVERT >>> Convert picture format (c)1997-2025 F&TSoft, version 2.76 OK colors 256

1st run Execution time: 1.570s
2nd run Execution time: 1.553s


ptime gm convert 20240826_074420G.jpg 20240826_074420G.gif
ptime 1.0 for Win32, Freeware - http://www.pc-tools.net/ Copyright(C) 2002, Jem Berkes <jberkes@pc-tools.net> === 
gm convert 20240826_074420G.jpg 20240826_074420G.gif ===

1st run Execution time: 2.847s
2nd run Execution time: 2.842s