If it is not valuable - why not? If you can control the moisture by opening a window or using an exhaust fan during showers (and a short time after to be sure you got rid of the steam) it should be okay. That said you will need to check for mold or mildew growth on all sides of the work from time to time. It would be advisable that if any art is valuable it be displayed or stored in a dry location with normal room temperatures. It also should be framed properly to archival standards if you wish to preserve and protect such valuables.
