Well for starters whyl are you using .gifs? The textures should be in .bmp format, .gif as far as I am aware isn't supported by SFC (not sure about SFC3) anyway they also reduce the quality of an image drastically.
M6 is an underated prog and it's what I still use because I'm not paying $20 for Milkshape - which is actually a proper modeling prog where you can create new meshes, it's quite commonly used because it's more easily available than progs like Max or Lightwave and so on which cost thousands.