The way that PowerStore works you will need to select the image to upload every time. One way you can use the images on your server would be to do this locally with the images directory that you will have on the server. This way you can browse to the images from your server and upload the image locally to make it go faster, then just make sure that the database and images get uploaded to the live server to ensure that is all matches.
If you already have the same images locally then this will not make much of a difference in your process though.