It's no longer considered a good idea to keep your static content under Apache and your dynamic content under Tomcat for simple performance reasons. If you need multiple apps to share these resources, that's different, but not because of some reason that became obsolete over a decade ago.
Please note that webapps don't "access" things like images. When you display a webpage with images, css, javascript, and/or other independent content, that content is not part of the webpage in the sense that the image data is embedded in the webpage datastream. Instead the image contains a URL that the
client will then open and obtain the image data from (in fact, in the days of slower modems, it was common for browsers to disable automatic fetching of images).
That URL can point anywhere in the world. Not only does it not have to be within the Tomcat webapp, it doesn't have to be on the same server, or literally even in the same country. Look at almost any commercial webpage and you'll see URL references to a whole host of third-party contributors.
So all you really need is an independent Apache source for the static content. You can do that by setting up a separate Apache VirtualHost for the images (say,
http://static.myhost.com/images/pic1.gif) or you can just do an Apache mod_rewrite to rewrite the image URL requests as Apache-hosted URLs.
Some people, when well-known sources tell them that fire will burn them, don't put their hands in the fire.
Some people, being skeptical, will put their hands in the fire, get burned, and learn not to put their hands in the fire.
And some people, believing that they know better than well-known sources, will claim it's a lie, put their hands in the fire, and continue to scream it's a lie even as their hands burn down to charred stumps.