If you are looking for a way how to export IGE GIS images to a TIFF one, you have to use the MrSID image encoder from ERDAS IMAGINE software. The programs supports a vast number of various graphics formats, so there should be no trouble with IGE to TIFF conversion.
Convert Erdas Imagine Large Raster Spill file to Aldus Tagged Image File Format (TIFF) bitmap image.
We found one software available in the database for this conversion.
Microsoft Windows software - convert ige to tiff on Windows
A Geospatial data authoring software
Convert from ige file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.