EnviroInsite does allow for the display of MrSID images. The code that processes those images is facilitated by public-domain libraries provided by Celartem, Inc. dba LizardTech. The EnviroInsite code grabs a user-specified portion of the MrSID image, processes that by down-sampling to user specifications and writes out an image file in the format specified by the user. That jpg file is automatically georeferenced and insert in the EnviroInsite view.
This dialog box allows for modification of the properties of the intermediate file created for insertion in EnviroInsite.