User is unable to attach a Raster file to a read-only DGN-file
It is not possible to attach a Raster file to a DGN that is read-only.When a raster image is attached, the information is written into the header of the DGN, and as the file is read-only, this can't be done.
In V8 version of MicroStation this was possible, because the File Open was written by Bentley.With the release of V8i the software was rewritten to accommodate WMS, ECWP and images from servers. For this MicroStation needed functionality from the Windows File Open.
To work around this; Open the Reference Manager to attach a raster image by setting Files of Type to All Files *.* and then select the raster.