...but do not erase localize attributes from image elements

...as these are used in xmlhelp/util/main_transform.xsl at runtime

Change-Id: I097cb79f660386d7fa2d97e7115f689a1e442fe2

xmlhelp/util/compact.xsl

@@ -24,6 +24,11 @@
     <!-- To remove attributes or nodes, 
          simply write a matching template that doesn't do anything. 
          Therefore, it is removed -->
+    <xsl:template match="image/@localize">
+        <xsl:copy>
+            <xsl:apply-templates select="@*[normalize-space()]|node()|text()"/>
+        </xsl:copy>
+    </xsl:template>
     <xsl:template match="@localize"/>
     <xsl:template match="@xml-lang"/>
     <xsl:template match="alt"/>