diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index d811f4d..e31dc1d 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1120,9 +1120,29 @@ function template_preprocess_links(&$variables) {
  *   - title: The title text is displayed when the image is hovered in some
  *     popular browsers.
  *   - attributes: Associative array of attributes to be placed in the img tag.
+ *   - srcset: Array of multiple URI's and sizes/multipliers.
  */
 function template_preprocess_image(&$variables) {
-  $variables['attributes']['src'] = file_create_url($variables['uri']);
+  if (!empty($variables['uri'])) {
+    $variables['attributes']['src'] = file_create_url($variables['uri']);
+  }
+  // Generate a srcset attribute conforming to the spec at
+  // http://www.w3.org/html/wg/drafts/html/master/embedded-content.html#attr-img-srcset
+  if (!empty($variables['srcset'])) {
+    $srcset = array();
+    foreach ($variables['srcset'] as $src) {
+      // URI is mandatory.
+      $source = file_create_url($src['uri']);
+      if (isset($src['width']) && !empty($src['width'])) {
+        $source .= ' ' . $src['width'];
+      }
+      elseif (isset($src['multiplier']) && !empty($src['multiplier'])) {
+        $source .= ' ' . $src['multiplier'];
+      }
+      $srcset[] = $source;
+    }
+    $variables['attributes']['srcset'] = implode(', ', $srcset);
+  }
 
   foreach (array('width', 'height', 'alt', 'title') as $key) {
     if (isset($variables[$key])) {
@@ -2287,7 +2307,7 @@ function drupal_common_theme() {
       // - http://dev.w3.org/html5/spec/Overview.html#alt
       // The title attribute is optional in all cases, so it is omitted by
       // default.
-      'variables' => array('uri' => NULL, 'width' => NULL, 'height' => NULL, 'alt' => '', 'title' => NULL, 'attributes' => array()),
+      'variables' => array('uri' => NULL, 'width' => NULL, 'height' => NULL, 'alt' => '', 'title' => NULL, 'attributes' => array(), 'srcset' => array()),
       'template' => 'image',
     ),
     'breadcrumb' => array(
diff --git a/core/modules/system/src/Tests/Theme/ImageTest.php b/core/modules/system/src/Tests/Theme/ImageTest.php
new file mode 100644
index 0000000..f37ef9b
--- /dev/null
+++ b/core/modules/system/src/Tests/Theme/ImageTest.php
@@ -0,0 +1,98 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\system\Tests\Theme\ImageTest.
+ */
+
+namespace Drupal\system\Tests\Theme;
+
+use Drupal\simpletest\DrupalUnitTestBase;
+
+/**
+ * Tests built-in image theme functions.
+ *
+ * @group Theme
+ */
+class ImageTest extends DrupalUnitTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('system');
+
+  /**
+   * The images to test with.
+   *
+   * @var array
+   */
+  protected $testImages;
+
+  protected function setUp() {
+    parent::setUp();
+    $this->testImages = array(
+      DRUPAL_ROOT . '/core/misc/druplicon.png',
+      DRUPAL_ROOT . '/core/misc/loading.gif',
+      DRUPAL_ROOT . '/core/misc/loading-small.gif',
+    );
+  }
+
+  /**
+   * Tests that an image with the src attribute is outputted correctly.
+   */
+  function testThemeImageWithSrc() {
+
+    $image = array(
+      '#theme' => 'image',
+      '#uri' => reset($this->testImages),
+      '#width' => rand(0, 1000) . 'px',
+      '#height' => rand(0, 500) . 'px',
+      '#alt' => $this->randomString(),
+      '#title' => $this->randomString(),
+    );
+    $this->render($image);
+    $this->removeWhiteSpace();
+    $expected = '<img src="' . $image['#uri'] . '" width="' . $image['#width']
+      . '" height="' . $image['#height'] . '" alt="' . $image['#alt']
+      . '" title="' . $image['#title'] . '" />';
+    $this->assertRaw($expected, 'Correct output for image with src attribute.');
+  }
+
+  /**
+   * Tests that an image with the srcset attribute is outputted correctly.
+   */
+  function testThemeImageWithSrcset() {
+    // Test with multipliers.
+    $image = array(
+      '#theme' => 'image',
+      '#srcset' => array(
+        array(
+          'uri' => $this->testImages[0],
+          'multiplier' => '1x',
+        ),
+        array(
+          'uri' => $this->testImages[1],
+          'multiplier' => '2x',
+        ),
+        array(
+          'uri' => $this->testImages[2],
+          'width' => '640w',
+        ),
+      ),
+      '#width' => rand(0, 1000) . 'px',
+      '#height' => rand(0, 500) . 'px',
+      '#alt' => $this->randomString(),
+      '#title' => $this->randomString(),
+    );
+    $this->render($image);
+    $this->removeWhiteSpace();
+    $expected = '<img srcset="' . $this->testImages[0] . ' 1x, '
+      . $this->testImages[1] . ' 2x, ' . $this->testImages[2] . ' 640w" width="'
+      . $image['#width'] . '" height="' . $image['#height'] . '" alt="'
+      . $image['#alt'] . '" title="' . $image['#title'] . '" />';
+    $this->assertRaw($expected, 'Correct output for image with srcset attribute.');
+  }
+
+}