Add issue about dropping <resolution> from image-set() in favor of just the 'x' unit.

Author: tabatkins

css4-images/Overview.html

@@ -887,6 +887,19 @@ <h3 id=image-set-notation><span class=secno>4.3. </span> Resolution
    href="#resolution-type"><i>&lt;resolution></i></a> is the image's <a
    href="#intrinsic-resolution"><i>intrinsic resolution</i></a>.
 
+  <p class=issue> It's been suggested that we don't need a full
+   &lt;resolution> here, and should instead just use the ‘<a
+   href="#x"><code class=css>x</code></a>’ unit by itself. This seems silly
+   to me, since the ‘<a href="#x"><code class=css>x</code></a>’ unit is
+   just an easier synonym for ‘<a href="#dppx"><code
+   class=css>dppx</code></a>’, but thoughts? Beyond theoretical purity
+   considerations, it seems that ‘<a href="#dpi"><code
+   class=css>dpi</code></a>’ can be useful for use-cases involving
+   printing, where dpi is actually used to talk about images and having an
+   integer correlation between dots and pixels is either unnecessary or
+   strictly non-sensical (as the screening resolution can depend on the
+   colors being used).
+
   <div class=example>
    <p> This example shows how to use ‘<code class=css>image-set()</code>’
     to provide an image in three versions: a "normal" version, a "high-res"

css4-images/Overview.src.html

@@ -599,6 +599,19 @@ <h3 id='image-set-notation'>
 		If an <i>&lt;image-set-decl></i> is chosen and successfully loaded,
 		the associated <i>&lt;resolution></i> is the image's <i>intrinsic resolution</i>.
 
+	<p class='issue'>
+		It's been suggested that we don't need a full &lt;resolution> here,
+		and should instead just use the ''x'' unit by itself.
+		This seems silly to me,
+		since the ''x'' unit is just an easier synonym for ''dppx'',
+		but thoughts?
+		Beyond theoretical purity considerations,
+		it seems that ''dpi'' can be useful for use-cases involving printing,
+		where dpi is actually used to talk about images
+		and having an integer correlation between dots and pixels
+		is either unnecessary or strictly non-sensical
+		(as the screening resolution can depend on the colors being used).
+
 	<div class='example'>
 		<p>
 			This example shows how to use ''image-set()'' to provide an image in three versions: