PHP page allowing the image file to be uploaded to an uploads directory. (Ensure its a valid image file and not a shell script that could allow hackers backdoor access to your site).
Once image is validated as true image. Store location of image in database. (e.g. - "images/image_file_name.jpg")
then call it through the display.php page in the <img src="$img" />
(keep in mind you have to run an SQL query to fetch the image location with a unique ID and attach it to the variable called $img.