simplify options
simplify options

internal memory format is always 32bpp, thus it contains the alpha channel
i-mars/jimp,kustomzone/jimp,kk9599/jimp,shaunstanislaus/jimp,oliver-moran/jimp,selaux/jimp,oliver-moran/jimp,bouchertommy/jimp,oliver-moran/jimp,mgh/jimp,neophob/jimp,neophob/jimp,bradparks/jimp__pure_javascript_lib_for_resize_grayscale_image_operations_no_dependencies,neophob/jimp,mubassirhayat/jimp,skoa-h/jimp,skoa-h/jimp,mgh/jimp,skoa-h/jimp