So Sites A,B,C are connected to each other via WAN, but sites B and C want to view Large Photoshop files from site A, to even view the files on a Mac or windows takes over 10 minutes as large thumbnails. These are directories with say 50 images but some are 50M some are north of 200M and they need to preview the images to ensure they are selecting the correct image.

It's painful. The links are around 100 / 200 mb from each site to our own ISP. (we don't go via the internet so this is all internal, Site > ISP > site.

Is there any MF replication technology that can give me a copy at each site and keep them in sync? We are highly unlikely to have two users working on the same image, but, we if possible need a way of being able to look at the data locally to save this long wait when just viewing the images in each directory. Or any other ideas on how to tackle this?