Document pixel dimension limit for WallpaperImage policy.

BUG=366825

Review URL: https://codereview.chromium.org/449483002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287816 0039d316-1c4b-4281-b951-d872f2087c98

components/policy/resources/policy_templates.json

@@ -6509,7 +6509,7 @@
       'caption': '''Wallpaper image''',
       'desc': '''Configure wallpaper image.
 
-      This policy allows you to configure the wallpaper image that is shown on the desktop and on the login screen background for the user. The policy is set by specifying the URL from which <ph name="PRODUCT_OS_NAME">$2<ex>Google Chrome OS</ex></ph> can download the wallpaper image and a cryptographic hash used to verify the integrity of the download. The image must be in JPEG format, its size must not exceed 16MB. The URL must be accessible without any authentication.
+      This policy allows you to configure the wallpaper image that is shown on the desktop and on the login screen background for the user. The policy is set by specifying the URL from which <ph name="PRODUCT_OS_NAME">$2<ex>Google Chrome OS</ex></ph> can download the wallpaper image and a cryptographic hash used to verify the integrity of the download. The image must be in JPEG format, its file size must not exceed 16MB and its dimension must not exceed 32 megapixels. The URL must be accessible without any authentication.
 
       The wallpaper image is downloaded and cached. It will be re-downloaded whenever the URL or the hash changes.