That should be: > > openr,lun,/GET_LUN,image_file > image=ASSOC(lun,fltarr(500,600)) ^^^^ > > sub_array=fltarr(201,201,4) > > for i=11,14 do begin > sub_array[0,0,i]=(image[i])[100:300,200:400] > endfor