Gallery.app : shows an error message when it fails to save an image.

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="chromeos">. -->
 <grit-part>
   <message name="IDS_EMPTY_STRING" desc="Empty string, exist only to make code generic. No translation required.">
   </message>
   <message name="IDS_CHROMEBOOK" desc="The localized name for Chromebook.">
     Chromebook
   </message>
   <message name="IDS_CHROMEBOX" desc="The localized name for Chromebox">
@@ skipping 337 matching lines @@
   </message>
   <message name="IDS_FILE_BROWSER_GALLERY_REDO" desc="In the Gallery, the text on the button that performs again the operation that has been recently reverted.">
     Redo
   </message>
   <message name="IDS_FILE_BROWSER_GALLERY_FILE_EXISTS" desc="In the Gallery, the message informing that file already exists when attempting to rename.">
     File already exists
   </message>
   <message name="IDS_FILE_BROWSER_GALLERY_SAVED" desc="In the Gallery, the message informing that editing saved successfully.">
     Saved
   </message>
+  <message name="IDS_FILE_BROWSER_GALLERY_SAVE_FAILED" desc="In the Gallery, the message informing that it failed to save editing image.">
+    Failed to save image.
+  </message>
   <message name="IDS_FILE_BROWSER_GALLERY_OVERWRITE_ORIGINAL" desc="In the Gallery, text on the button to overwrite original file along with the edited copy.">
     Overwrite original
   </message>
   <message name="IDS_FILE_BROWSER_GALLERY_OVERWRITE_BUBBLE" desc="In the Gallery, text in the bubble informing user about saving and overwriting original file.">
     Your edits are saved automatically.<ph name="BREAKS">&lt;br&gt;&lt;br&gt;<ex>&lt;br&gt;&lt;br&gt;</ex></ph>To keep a copy of the original image, uncheck "Overwrite original"
   </message>
   <message name="IDS_FILE_BROWSER_GALLERY_READONLY_WARNING" desc="In the Gallery, message informing that directory is readonly, and edited files will be saved to Downloads directory.">
     Cannot save to $1. Edited images will be saved in the Downloads folder.
   </message>
   <message name="IDS_FILE_BROWSER_GALLERY_IMAGE_ERROR" desc="In the Gallery, message informing that the image failed to load.">
@@ skipping 5715 matching lines @@
   <message name="IDS_FLAGS_DISABLE_RESOLVE_TIMEZONE_BY_GEOLOCATION_DESCRIPTION" desc="Description for the flag to disable user setting to automatically update timezone by user geolocation.">
     If set, automatic timezone update by the current geolocation is turned off.
   </message>
   <message name="IDS_OPTIONS_RESOLVE_TIMEZONE_BY_GEOLOCATION_DESCRIPTION" desc="Label for checkbox to allow automatic timezone update by user geolocation.">
     Set time zone automatically using your location
   </message>
   <message name="IDS_OPTIONS_CAPTIVE_PORTAL_BYPASS_PROXY_LABEL" desc="Option in chrome://settings that allows Captive Portal authorization pages to ignore proxy settings.">
     Allow captive portal sign-in page to bypass proxy servers
   </message>
 </grit-part>