How do you insert a raster of unknown scale?

[engineeringh2o]

I have a raster image (CIT) that I need to insert into Microstation preferable so that it scales appropriately (1:1). I know drawing's scale is 1"=100', but I do not know the original border size. I have IRASB version 7.1 and Microstation version 7/J.

Can anybody help? Thank you.

 

[bardoc]

Suggestion. If you use 1/8" text height, place some text and then import the image and adjust it until the image text is about the same size as your text. This will bring the size to approx. what you need.