Make proposal images work in github repository rendering

proposals/VK_EXT_device_generated_commands.adoc

@@ -6,6 +6,8 @@
 :toc: left
 :refpage: https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/
 :sectnums:
+// Required so images render in github
+ifndef::images[:images: ..]
 
 This document details API design for indirect execution of device generated commands, improving performance by eliminating unnecessary host and device work.
 

proposals/VK_EXT_shader_tile_image.adoc

@@ -6,6 +6,8 @@
 :toc: left
 :refpage: https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/
 :sectnums:
+// Required so images render in github
+ifndef::images[:images: ..]
 
 `VK_EXT_shader_tile_image` is a device extension that explicitly enables access to on-chip pixel data. For GPUs supporting this extension, it is a replacement for many use-cases for subpasses, which are not available when the `VK_KHR_dynamic_rendering` extension is used.
 
@@ -85,7 +87,7 @@ Tile image variables currently have to 'alias' a color attachment location, and
 
 === Concept
 
-image::{images}/tile_image.svg[align="center",title="Tile Image",align="center",opts="{imageopts}"]
+image::{images}/proposals/tile_image.svg[align="center",title="Tile Image",align="center",opts="{imageopts}"]
 
 Introduce the concept of a 'tile image'. When the extension is enabled, the framebuffer is logically divided into a grid of non-overlapping tiles called tile images.
 

proposals/template.adoc

@@ -6,6 +6,13 @@
 :toc: left
 :refpage: https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/
 :sectnums:
+// Required so images render in github
+ifndef::images[:images: ..]
+
+// NOTE:
+// If adding an image to a proposal document, it must be located in
+// ../images/proposals/, and referred to as
+// image::{images}/proposals/filename.svg[image options]
 
 .How to Use This Document
 [NOTE]