Follow these steps
1) Choose the layer in the Table of contents, right click on it, and choose properties.
2) Go to the Symbology tab and press on the symbol properties.
3) In the window that opened in the type combobox choose the last option (picture symbol).
4) Choose the picture (you can choose bmp or emf).
And there you have it.
(Oh: I used 9.3.1)