Hotlinking and image download

I hope and someone can help me with this issue. You see, I have a website where I require that the images cannot be subtracted. I thought about doing a hotlinking through the cpanel, which is what I am looking for. But ... I also require that users who are logged in can download the images, and at the time of hotlinking these cannot be downloaded. Could someone advise me what I could do to protect the real images and download them in my domain? Sorry if my English is not very good, I still don't know that topic well: S thanks.