Answer
Developers can use MapObjects in conjunction with the ArcIMS middleware in order to publish maps to the Web. See the "MapObjects Internet Developer Kit" product. The ESRI WebLink control that ships with MapObjects provides the ability to convert from a BMP to a GIF. In fact, the MapObjects-Windows software supports the creation of both JFIF (JPEG) and GIF formats to deliver images/maps over the Internet.
Since the GIF format utilized the LZW compression technology patented by UNISYS Corporation, MapObjects developers were obligated to establish a licensing agreement with UNISYS before using the BMP2GIF method in MapObjects. In fact, ESRI was required to restrict write capabilities for GIF or TIFF/LZW in all ESRI products.
Recently, the UNISYS patent on the LZW technology expired, worldwide. Consequently, it is no longer necessary to request additional licensing from UNISYS, nor complementary keycodes from ESRI.
In sum, the following license string can be used for unlocking the write capabilities in MapObjects on the WebLink control to generate the GIF format.
Weblink1.EnableGIF "UM97414567"