Since I know nothing about JSP and ColdFusion... Maybe you can give me/us a look at what you mean?
For example: I don't know what you mean with: "The image tag invoked alone in JSP".
I think both, CF and JSP give you a html-file. Each file contains the image-tag. Each file is displayed in a browser. The CF-generated file is okay, the JSP-Generated file contains a broken image, right?