input,s,a,"",,,Input image name
output,s,h,"",,,Output root name
clobber,b,h,"yes",,,Clobber prexisting subimages
#xskip1,i,h,INDEF,0,,X pixels to skip at start of overscan
#xskip2,i,h,INDEF,0,,X pixels to skip at end of overscan
#xtrim1,i,h,INDEF,0,,X pixels to trim at start of data
#xtrim2,i,h,INDEF,0,,X pixels to trim at end   of data
#ytrim1,i,h,INDEF,0,,Y pixels to trim at start of data
#ytrim2,i,h,INDEF,0,,Y pixels to trim at end   of data