Imagemagik Change an images dpi from 400 to 72

Question

I have an image on my server which I know the dpi of and if it's too high I want to size it down to 72 I still want to keep the same height and width of the image. Any ideas?

I've played around with -resample -units and -density but don't seem to be getting anywhere and can't find any answers. Anyone out there that can help

Answer 1

According to this using density should work

Answer 2

If you know the target dpi and the width/height (in pixels) then you can just resize the image that meets those targets.