[css-sizing-3][editorial] Add width/height to the SVG images.

Author: tabatkins

css-sizing-3/Overview.bs

@@ -100,11 +100,11 @@ Terminology</h2>
 			alternatively a [=width=] and/or [=height=].
 
 			<figure>
-				<img style="max-width: 49%;" src="images/sizing-ltr-tb.svg"
+				<img style="max-width: 49%;" width=420 height=240 src="images/sizing-ltr-tb.svg"
 				     alt="In left-to-right, top-to-bottom horizontal English,
 				          the horizontal width and inline size are synonymous,
 				          and vertical height and block size are synonymous."><!--
-				--><img style="max-width: 49%;" src="images/sizing-ttb-rl.svg"
+				--><img style="max-width: 49%;" width=420 height=240 src="images/sizing-ttb-rl.svg"
 				      alt="In top-to-bottom, right-to-left vertical Japanese,
 				           the horizontal width and block size are synonymous,
 				           and vertical height and inline size are synonymous.">
@@ -117,7 +117,7 @@ Terminology</h2>
 			The <a href="https://www.w3.org/TR/css2/box.html#box-dimensions">content-box</a> [=size=] of a <a>box</a>.
 
 			<figure>
-				<img src="images/inner-size.svg" alt="">
+				<img src="images/inner-size.svg" width=420 height=270 alt="">
 				<figcaption>Inner size</figcaption>
 			</figure>
 
@@ -126,7 +126,7 @@ Terminology</h2>
 			The <a href="https://www.w3.org/TR/css2/box.html#box-dimensions">margin-box</a> [=size=] of a <a>box</a>.
 
 			<figure>
-				<img src="images/outer-size.svg" alt="">
+				<img src="images/outer-size.svg" width=420 height=270 alt="">
 				<figcaption>Outer size</figcaption>
 			</figure>