diff --git a/img/cube.jpg b/img/cube.jpg
new file mode 100644
index 0000000..36b67f3
Binary files /dev/null and b/img/cube.jpg differ
diff --git a/index.html b/index.html
index 2e6d1f8..0b1b95c 100644
--- a/index.html
+++ b/index.html
@@ -104,6 +104,7 @@
             <p>Before general calibration or before a significant modification is to be fitted.</p>
         </div>
         <p>The form below will create a customised version of the <a href="https://www.thingiverse.com/thing:1278865" target="_blank">XYZ 20mm calibration cube by iDig3Dprinting</a>. It is fast to print and gives a good indication if there is any fundamental problem with the printer.</p>
+        <a href="#" data-featherlight="img/cube.jpg"><img class="thumb" src="img/cube.jpg" /></a>
         <form name="baselineForm" id="baselineForm" onsubmit="return:false;">
             <h4>Bed dimensions</h4>
             <p>Inputting the correct number will attempt to move the print into the centre of the bed. In the centre button is checked, the bed size is irrelevant. Please check the gcode to ensure it will fit on your bed.</p>