diff --git a/gtk/gtkcssimage.c b/gtk/gtkcssimage.c
index 29d9959d8b..822ba4726f 100644
--- a/gtk/gtkcssimage.c
+++ b/gtk/gtkcssimage.c
@@ -358,13 +358,13 @@ _gtk_css_image_get_concrete_size (GtkCssImage *image,
         {
           if (image_aspect * default_height > default_width)
             {
-              *concrete_width = default_height * image_aspect;
-              *concrete_height = default_height;
+              *concrete_width = default_width;
+              *concrete_height = default_width / image_aspect;
             }
           else
             {
-              *concrete_width = default_width;
-              *concrete_height = default_width / image_aspect;
+              *concrete_width = default_height * image_aspect;
+              *concrete_height = default_height;
             }
         }
       else
diff --git a/testsuite/reftests/Makefile.am b/testsuite/reftests/Makefile.am
index 2dbca1209c..31645d23f0 100644
--- a/testsuite/reftests/Makefile.am
+++ b/testsuite/reftests/Makefile.am
@@ -198,6 +198,9 @@ testdata = \
 	css-currentcolor-alpha.css \
 	css-currentcolor-alpha.ui \
 	css-currentcolor-alpha.ref.ui \
+	css-image-aspect-ratio.css \
+	css-image-aspect-ratio.ui \
+	css-image-aspect-ratio.ref.ui \
 	css-match-class.css \
 	css-match-class.ref.ui \
 	css-match-class.ui \
diff --git a/testsuite/reftests/css-image-aspect-ratio.css b/testsuite/reftests/css-image-aspect-ratio.css
new file mode 100644
index 0000000000..da054daa16
--- /dev/null
+++ b/testsuite/reftests/css-image-aspect-ratio.css
@@ -0,0 +1,8 @@
+window {
+  background-image: -gtk-icontheme("edit-delete");
+  background-repeat: no-repeat;
+}
+
+#reference {
+  background-size: 24px 24px;
+}
diff --git a/testsuite/reftests/css-image-aspect-ratio.ref.ui b/testsuite/reftests/css-image-aspect-ratio.ref.ui
new file mode 100644
index 0000000000..88fbd72e75
--- /dev/null
+++ b/testsuite/reftests/css-image-aspect-ratio.ref.ui
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <!-- interface-requires gtk+ 3.0 -->
+  <object class="GtkWindow" id="window1">
+    <property name="width_request">48</property>
+    <property name="height_request">24</property>
+    <property name="can_focus">False</property>
+    <property name="type">popup</property>
+    <property name="name">reference</property>
+  </object>
+</interface>
diff --git a/testsuite/reftests/css-image-aspect-ratio.ui b/testsuite/reftests/css-image-aspect-ratio.ui
new file mode 100644
index 0000000000..c7f559893b
--- /dev/null
+++ b/testsuite/reftests/css-image-aspect-ratio.ui
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <!-- interface-requires gtk+ 3.0 -->
+  <object class="GtkWindow" id="window1">
+    <property name="width_request">48</property>
+    <property name="height_request">24</property>
+    <property name="can_focus">False</property>
+    <property name="type">popup</property>
+  </object>
+</interface>