PHP Array containing the names of all (but one) Folder in a Given Directory

So, I have a directory, called "images". Within that directory, I have a bunch of folders containing images. I would like a PHP array of the names of those folders.

One hiccup: I also have one "includes" folder in the directory which I don't want in the array.

If it helps, the folders I want all have the same "date_filenumber" ("YYYYMMDD_1234") naming patttern, which of course "includes" does not.

I plan to select one of the images at random to display on my landing page.

Please correct me if I'm wrong, but my understanding is that all I need is:

*PHP*

$array = [whatever gets me the list mentioned above]
$random = array_rand($array)


*HTML*

<img src="<?php echo 'images/'.$random.'0x.jpg';?>">

Thanks!