Specific image identifier; e.g. Wooden Sword or Armos. This is part of the filename.
File extension; "png" is default.
Optional image parameters; will override default height constraint of 32px, so you will need to re-specify like "x20px" (height constraint) or "30px" (width constraint) or 30x20px (width x height constraints). To add additional parameters, use {{!}} to escape the pipe character to separate image parameters. See example below with the thumbnail (note: do not use thumbnail or float parameters with in-line images).
s: Switch sides. This moves the text to the right side of the icon. Useful for aligning the image.