I know about the PNG thread, but we should really be looking into setting a standard for the Wiki. Do we see this as an extension of what the museum would be? Typically you would be looking at a .TIFF format. This site has a good starting point for resolution and DPI. http://www.archives.gov/records-mgmt/initiatives/digital-photo-records.html Just something to think about as it is something Ive worked on during my Master's program.