Adjusted documentation for light/dark images in custom color schemes

Author: squidfunk

Diff for: docs/reference/images.md

@@ -172,7 +172,37 @@ hash fragment to the image URL:
 
 </div>
 
+!!! warning "Requirements when using [custom color schemes]"
+
+    The built-in [color schemes] define the aforementioned hash fragments, but
+    if you're using [custom color schemes], you'll also have to add the
+    following selectors to your scheme, depending on whether it's a light or
+    dark scheme:
+
+    === "Custom light scheme"
+
+        ``` css
+        [data-md-color-scheme="custom-light"] img[src$="#only-dark"]
+        [data-md-color-scheme="custom-light"] img[src$="#gh-dark-mode-only"] {
+          display: none; /* Hide dark images in light mode */
+        }
+        ```
+
+    === "Custom dark scheme"
+
+        ``` css
+        [data-md-color-scheme="custom-dark"] img[src$="#only-light"],
+        [data-md-color-scheme="custom-dark"] img[src$="#gh-light-mode-only"] {
+          display: none; /* Hide light images in dark mode */
+        }
+        ```
+
+    Remember to change `#!css "custom-light"` and `#!css "custom-dark"` to the
+    name of your scheme.
+
   [Light and dark mode support]: https://github.com/squidfunk/mkdocs-material/releases/tag/8.1.1
   [color palette toggle]: ../setup/changing-the-colors.md#color-palette-toggle
   [Zelda light world]: ../assets/images/zelda-light-world.png#only-light
   [Zelda dark world]: ../assets/images/zelda-dark-world.png#only-dark
+  [color schemes]: ../setup/changing-the-colors.md#color-scheme
+  [custom color schemes]: ../setup/changing-the-colors.md#custom-color-schemes