https://eab.abime.net/showpost.php?p...4&postcount=83
^ Thats an recentish post of me showing Using Gimp to load pictures and create 8/16 color MWB IFF's, even saving the indexed colormaps for quick future use, gimp has several old and some current(ish) IFF/ILBM/Amiga plugins to load/save perfectly fine.
included snap of the plugin i use, as i recall its 1 of the older ones and people state there are newer/better, but i havent had any issues with my older one as of yet, tho i think the one i have doesnt handle Hams's even tho it says it does.