The ExpressView Browser Plug-in (formerly MrSID Browser Plug-in) from LizardTech opens MrSID as well as JPEG 2000 images. The Plug-in provides advanced viewing controls, including zoom-in/out for detail inspection. ExpressView is supported by both Microsoft Windows and Apple's Mac OS. The Plug-in is available free for individual use from the LizardTech website. Click on the link at left to connect to the download site and instructions.
MrSID (Multi-Resolution Seamless Image Database) is a wavelet based image encoder, viewer, and file format designed specifically for imaging and GIS professionals. Developed and marketed by LizardTech, it offers instantaneous viewing, panning and zooming of high resolution images. MrSID images have the file extension ".sid"
The newer JPEG 2000 image format (a project of the Joint Photographic Experts Group) is also capable of providing multi-resolution, zoomable displays. Columbia University's Libraries Digital Program began using JPEG 2000 in preference to MrSID in mid-2005. JPEG 2000 images created by CUL have the file extension ".jp2"