Well, from a gallery visitor's point of view, what kind of function would you like to have? Would a visitor like to take a random stroll? Would they like to view everything by one artist? Would they like to see the newest works in the gallery? Would they like to search by one or more keywords (e.g., landscape, still life, portrait, media, style, etc.)? All of these can be done, but will take a database to hold references to works along with date, keywords, artist, title, price, etc. and be sorted accordingly. Do you want a visitor to be able to zoom in on an image to see a detail?
From the gallery owner/manager's point of view, how often do works come in and others get sold or returned to the artist? Do you want separate thumbnail and "full size" images? I'm guessing that you want to be able to quickly make changes, without manual editing and uploading. Even if you disable the shopping cart and checkout, and act just as a catalog, many eCommerce solutions can handle all this for you, so don't rule that out simply because you don't plan to sell online. You will need to do some minor modifications to change "manufacturer" to "artist", "product" to "work", etc., and hide the shopping cart and checkout.
Hopefully this discussion will get some others to chime in with their thoughts.