Options.You have many different options for customizing the scaling of MicroStation DGN images. First, you can select whether DGN files are automatically scaled to a specific size, or whether an input scale factor is applied to them.
To automatically scale DGN images on open:
1. Choose Preference Options.
2. Click the 
beside
Format.
3. Click MicroStation DGN.
4. Under Scaling, make sure that Scale To Fit is selected.
5. Select the width, length, and units to which you want DGN images to be scaled.
6. Click Save. Click OK.
On open, MicroStation images are now scaled to the page size you specified.
To disable automatic scaling and define an input scale factor for DGN images:
1. Choose Preference Options.
2. Click the beside
Format.
3. Click MicroStation DGN.
4. Under Scaling, click Scale Factor.
5. After "1 Unit =", type or select the scale factor to apply to DGN images on open. Type the equivalent value in inches or cm.
6. Click Save. Click OK.
Newly opened DGN images will be displayed at the specified scale factor. (Currently open DGN images are not affected.)
To define how DGN files are scaled on import, you can edit the Image.ini file.
To automatically scale DGN images on import:
1. Open the Image.ini file in a text editor.
2. In the [File] section, find the Use Raster Mapping on Vector Load= keyname. After the equal sign, type 1. This makes MicroStation images fit over the raster image and take on its resolution on import.
3. Save the Image.ini file, and close it.
When you restart Imagenation, the change takes effect. On import, DGN images fit over the raster image on the page (if any).