Is there an html "spoiler tag" equivalent on this forum?

[KevKiev]

I'm drafting a post in which I'll have a few images and, to save space and keep things tidy, I was trying to insert them into spoiler tags i.e. sandwiching the images between "[spoiler]" and "[/spoiler]" which, on the (few) other forums I frequent, results in a text box that you can click on to expand and see what's between the tags and click again to hide. (Sorry if that's ridiculously old news.) But when I preview the post, the image is simply displayed between with the tags as plain text.

I tried using the "code" button, with "spoiler" alone and with brackets, but that didn't work.  (I have no idea what "PHP" is, but I tried that button unsuccessfully too.)

Thanks