Slash Markup cheat sheet
Put optional display prefixes immediately before a file code or video URL.
A file code on its own produces a text link using the file’s name.
The /// end marker below separates a code or URL from adjoining text.

t200/       Thumbnail 200 px wide (100-4096)
            For images and video URLs
p500/       Popup 500 px wide (200-8192)
            For everything that opens in a popup
r30/        Corners rounded by 30 px
            For images and video thumbnails
/Your words/  Your own words become the link
            Put it first when you combine prefixes
ttl Caption/  Caption under the image in the popup
            For images
np/         Show the image on the page, no popup
            It is also left out of the gallery
n/          Video title as a text link, no thumbnail
            For video URLs
///         End marker
            Put it right after the code or URL
            when text or punctuation follows without a space

Combine them:
t300/r30/code
/Play the video/p500/code

Widths are maximums. Items shrink to fit narrower spaces.
Full details are in the Readme tab of the control panel.