Once a GIF license has been obtained, the aimsms.cfg file must be updated in order to activate GIF capabilities.
NOTE: A GIF license specifically for ArcIMS is required. MapObjects IMS and ArcView IMS GIF licenses will not work with ArcIMS.
<servercomponent type = "ImageServer"
description = "My Image Server"
exe = "MapServer\aimsms.dll"
<parameter name="giflicense" value="A12B3C4D5E" />
Please see the article in the Related Information section (below) to obtain a valid key code for GIF images