Hi Blic, that looks fine to me. The syntax is the same as the good old DOS command (with the slashes the opposite way round), and Bash shell etc.
Actually you should also be able to use absolute paths, but the root "/" is the web server root
as seen by the clients browser (which is not necessarily the same as the root you see in FTP client).
Relative paths are simpler to put in a distributed script, as if the folders are uploaded per the .zip, then the images folder will always be "images/" relative to the supplied HTML page no matter where it actually resides in the web server folder structure. I probably making this less clear the more I type!