diff --git a/info.yaml-format-info.md b/info.yaml-format-info.md
index 08c8892..d578ea0 100644
--- a/info.yaml-format-info.md
+++ b/info.yaml-format-info.md
@@ -149,7 +149,11 @@ a single filename for the thumbnail used in gallery views. if left off, then the
 
 ## bg
 
-anything that can be the value of a css `background` property. a colour, a gradient, another image listed in `extras`, several of those, whatever. obviously if you go too crazy it starts becoming part of the image itself but whatever. it's optional, since it only matters for images with transparency.
+options:
+
+- absent (or `null`)
+- anything that can be the value of a css `background` property. a colour, a gradient, another image listed in `extras`, several of those, whatever
+- the magic word `noborder` (case sensitive) to remove the default background, border, shadow
 
 ## links