At times we use custom images in controls (image controls) or as Graphic buttons. These have to be placed appropriately to be shown on Web and during development
While in development (for FDA), the location is C:\E900\DV900\res\image.bmp
In Web-dev it resides at C:\E900\system\OC4J\j2ee\home\applications\webclient.ear\webclient\img\res\image.gif
So place it appropriately while deployed to the server as well.
The web run-time expects a .gif file, so make sure, your .bmp is converted into a .gif file.