diff --git a/core/server/lib/mobiledoc.js b/core/server/lib/mobiledoc.js
index 32a86b1f9f..6ef6681241 100644
--- a/core/server/lib/mobiledoc.js
+++ b/core/server/lib/mobiledoc.js
@@ -28,7 +28,8 @@ module.exports = {
 
             cardFactory = new CardFactory({
                 siteUrl: config.get('url'),
-                contentImageSizes: config.get('imageOptimization:contentImageSizes')
+                contentImageSizes: config.get('imageOptimization:contentImageSizes'),
+                srcsets: config.get('imageOptimization:srcsets')
             });
 
             cards = defaultCards.map((card) => {
@@ -75,5 +76,12 @@ module.exports = {
                 });
             };
         }
+    },
+
+    // allow config changes to be picked up - useful in tests
+    reload() {
+        cardFactory = null;
+        cards = null;
+        mobiledocHtmlRenderer = null;
     }
 };
diff --git a/core/shared/config/defaults.json b/core/shared/config/defaults.json
index 159e443566..342cf77068 100644
--- a/core/shared/config/defaults.json
+++ b/core/shared/config/defaults.json
@@ -102,7 +102,8 @@
         }
     },
     "imageOptimization": {
-        "resize": true
+        "resize": true,
+        "srcsets": true
     },
     "compress": true,
     "preloadHeaders": false,
diff --git a/test/unit/lib/mobiledoc_spec.js b/test/unit/lib/mobiledoc_spec.js
index a14402581b..2d16c8681a 100644
--- a/test/unit/lib/mobiledoc_spec.js
+++ b/test/unit/lib/mobiledoc_spec.js
@@ -9,6 +9,8 @@ describe('lib/mobiledoc', function () {
 
     afterEach(function () {
         configUtils.restore();
+        // ensure config changes are reset and picked up by next test
+        mobiledocLib.reload();
     });
 
     describe('mobiledocHtmlRenderer', function () {
@@ -72,5 +74,40 @@ describe('lib/mobiledoc', function () {
             mobiledocLib.mobiledocHtmlRenderer.render(mobiledoc)
                 .should.eql('<p>One<br>Two</p><!--kg-card-begin: markdown--><h1 id="markdowncard">Markdown card</h1>\n<p>Some markdown</p>\n<!--kg-card-end: markdown--><p>Three</p><hr><figure class="kg-card kg-image-card kg-width-wide kg-card-hascaption"><img src="/content/images/2018/04/NatGeo06.jpg" class="kg-image" alt srcset="/content/images/size/w600/2018/04/NatGeo06.jpg 600w, /content/images/size/w1000/2018/04/NatGeo06.jpg 1000w, /content/images/size/w1600/2018/04/NatGeo06.jpg 1600w, /content/images/size/w2400/2018/04/NatGeo06.jpg 2400w"><figcaption>Birdies</figcaption></figure><p>Four</p><!--kg-card-begin: html--><h2>HTML card</h2>\n<div><p>Some HTML</p></div><!--kg-card-end: html--><figure class="kg-card kg-embed-card"><h2>Embed card</h2></figure><figure class="kg-card kg-gallery-card kg-width-wide"><div class="kg-gallery-container"><div class="kg-gallery-row"><div class="kg-gallery-image"><img src="/content/images/test.png" width="1000" height="500" alt srcset="/content/images/size/w600/test.png 600w, /content/images/size/w1000/test.png 1000w"></div></div></div></figure>');
         });
+
+        it('respects srcsets config', function () {
+            configUtils.set('imageOptimization:srcsets', false);
+
+            let mobiledoc = {
+                version: '0.3.1',
+                atoms: [],
+                cards: [
+                    ['image', {
+                        cardWidth: 'wide',
+                        src: '/content/images/2018/04/NatGeo06.jpg',
+                        width: 4000,
+                        height: 2000,
+                        caption: 'Birdies'
+                    }],
+                    ['gallery', {
+                        images: [{
+                            row: 0,
+                            fileName: 'test.png',
+                            src: '/content/images/test.png',
+                            width: 1000,
+                            height: 500
+                        }]
+                    }]
+                ],
+                markups: [],
+                sections: [
+                    [10, 0],
+                    [10, 1]
+                ]
+            };
+
+            mobiledocLib.mobiledocHtmlRenderer.render(mobiledoc)
+                .should.eql('<figure class="kg-card kg-image-card kg-width-wide kg-card-hascaption"><img src="/content/images/2018/04/NatGeo06.jpg" class="kg-image" alt><figcaption>Birdies</figcaption></figure><figure class="kg-card kg-gallery-card kg-width-wide"><div class="kg-gallery-container"><div class="kg-gallery-row"><div class="kg-gallery-image"><img src="/content/images/test.png" width="1000" height="500" alt></div></div></div></figure>');
+        });
     });
 });