Issue #402

This test-case is intended for Issue #402 - Net tab tries to show previews of non-images with image file extensions.
Jan Odvarko, odvarko@gmail.com

• image1.jpeg - Content-Type: text/plain
• image2.gif - Content-Type: nonexisting/mimetype
• image3.php - Content-Type: image/png

Open Firebug's Net panel and hover mouse over all these files.

1. The preview should not be displayed for image1.jpeg.
2. The preview should be wrongly displayed (only wait icon) for image2.gif as the content-type is unknown and FB uses the file extension to guess it.
3. The preview should be properly displayed for image3.php as the content-type is correct and preferred.

Try it twice and make sure that it works even if image1.jpeg and image2.gif come from the cache.