Some button icons display badimage.gif and some display correct image .gif

I created icon.jar and stored it in ...\forms\java alongside frmall.jar and the rest.  In the default.env file I have set imagebase = codebase and I have a standard toolbar canvas filled with iconic buttons for various standard functions (save, exit, up arrow, help, etc).  When I run the forms, some of the buttons display the correct icon image but most are replaced by badimage.gif.  From the java console trace record I cannot see why this might be happening. The following is an excerpt from the java trace log.

basic: Loaded image: jar:http://oradev64:7001/forms/java/icons.jar!/save.gif