A few years ago it was deemed state-of-the-art to store any kind of extra resources (images, css/js-files) directly on the webserver.
Of course this was just the best-practice, left with many who were not able to follow because of company restrictions: no access to web server, not allowed to store files, too many regulations, and so on.
Luckily APEX 5++ gave us nicely working Static Application Files and Static Workspace Files. Now everyone is using those to store extra files.