int im_bandjoin(im1, im2, imout)
IMAGE *im1, *im2, *imout;
int im_gbandjoin(imarray, imout, no)
IMAGE *imarray[], *imout;
int no;
im_bandjoin() performs a band-wise join of two images. If the two images have n and m bands respectively, then the output image will have n+m bands, with the first n coming from the first image and the last m from the second.
im_gbandjoin() performs a generalised band-wise join of no images. Input images can have any number of bands; for instance if imarray[0] has j bands, imarray[1] has k bands, ...., imarray[no-1] has z bands, output has j+k+...+z bands.