ERDAS IMAGINE software keeps image data in .ige and .img files, with the raster data itself saved in the IGE format. But for successful ige to tif conversion or export, it might be very well possible that you will need both files.
We did not find any useful information about ige to tif conversion or export, so if you struggle with it, or need something specific, it might be best to reach out to ERDAS support or online community.
Updated: October 4, 2023