Size to resize to, to hit `targ_sz` at same aspect ratio, in PIL coords (i.e w*h)

def resize_to(img, targ_sz:int, use_min:bool=False):
    "Size to resize to, to hit `targ_sz` at same aspect ratio, in PIL coords (i.e w*h)"
    w,h = img.size
    min_sz = (min if use_min else max)(w,h)
    ratio = targ_sz/min_sz
    return int(w*ratio),int(h*ratio)