Hi Hsieh
you have almost guessed the answer yourself, as your headline about the "Context root" is the answer.
The reason why the first "../visage.gif" is not shown and the second "visage.gif" is shown is that the WebContent folder ifself in your web project does not exist when the project is deployed.
What is deployed is only the files + sub-folders inside the WebContent folder, and therefore is the phrase "../" (that should identify the folder containing the visage.gif) not valid.
The visage.gif is located in the root folder - also named the web "Context root".
Hope that explains your problem.
btw. in the future I guess you will add your own *.gif files to a sub-folder named "images" or similar. In that case the reference to the file must be a relative path SRC="images/visage.gif"
Best Regards
Morten Hansen, IBM Denmark
mohaIBMDK