Since you consider my comment to the question "pointless" I will help you out...
Apache's Alias directive operates on paths, but rewriting easily allows what you are looking for:
RewriteEngine on
RewriteCond %{HTTP_HOST} ^([^.]+)\.example\.com$
RewriteRule ^/?images/(.*)$ /path/to/%1/images/$1 [QSA,END]
In case you receive an internal server error (http status 500) using the rule above then chances are that you operate a very old version of the apache http server. You will see a definite hint to an unsupported [END] flag in your http servers error log file in that case. You can either try to upgrade or use the older [L] flag, it probably will work the same in this situation, though that depends a bit on your setup.
This implementation will work likewise in the http servers host configuration or inside a distributed configuration file (".htaccess" file). Obviously the rewriting module needs to be loaded inside the http server and enabled in the http host. In case you use a distributed configuration file you need to take care that it's interpretation is enabled at all in the host configuration and that it is located in the host's DOCUMENT_ROOT folder.
And a general remark: you should always prefer to place such rules in the http servers host configuration instead of using distributed configuration files (".htaccess"). Those distributed configuration files add complexity, are often a cause of unexpected behavior, hard to debug and they really slow down the http server. They are only provided as a last option for situations where you do not have access to the real http servers host configuration (read: really cheap service providers) or for applications insisting on writing their own rules (which is an obvious security nightmare).
And to come back to my initial comment to your question here is a spontaneous collection of existing answers here on SO demonstrating the same thing:
