TG4 Conversion - How To??

Intergraph TG4 raster format is supported in Raster Manager.  In Raster Manager have you tried doing Raster Manager > File > Batch Convert.  You can also attach the .TG4 image in Raster Manager and right click on the raster image name and select Save As and select the raster format that you want to use.

Environment Variable:

MS_INGRFILE_REGISTRATION User defined.
Sets File Georeference priority over attachment location for Intergraph raster formats, essentially CIT, C29, C30, C31, COT, RLE, TG4 and RGB raster formats.
If undefined or set to 0, there is no effect.
If set to 1, enables File Georeference priority for rasters.

https://communities.bentley.com/products/microstation/f/z_-archived-microstation-v8i-forum/69587/tg4---the-file-type-is-no-supported---13-error/181746#181746

Intergraph TG4 raster format is supported in Raster Manager.  In Raster Manager have you tried doing Raster Manager > File > Batch Convert.  You can also attach the .TG4 image in Raster Manager and right click on the raster image name and select Save As and select the raster format that you want to use.

Environment Variable:

MS_INGRFILE_REGISTRATION User defined.
Sets File Georeference priority over attachment location for Intergraph raster formats, essentially CIT, C29, C30, C31, COT, RLE, TG4 and RGB raster formats.
If undefined or set to 0, there is no effect.
If set to 1, enables File Georeference priority for rasters.

https://communities.bentley.com/products/microstation/f/z_-archived-microstation-v8i-forum/69587/tg4---the-file-type-is-no-supported---13-error/181746#181746

We used to use the batch converter in MicroStation for this, but we let our Microstation license expire as we no longer needed it for drawings. But a client of ours has thousands of buildings where the historic documentation is in TG4 format. Would love to just find something simple to convert to PNG without having to buy MicroStation again just for the single purpose of converting images.