For the ships at least, you can use standard *.bmp format textures, I am sure the same is true for the planets.
@ Smiley, you have good points, however, I know for myself, playing SFC1 helps me remember events surrounding the first time I played SFC, the friends I knew, the music I listened to, the job I worked at. It has tons of setimental value to me. I am sure many people will say the same.