Firefox won't show an image

[Carstonio]

Firefox 3.5.3 is giving me a strange error. One particular image on a page will not display when the page is loaded from my Web site. The image is visible when I enter the URL directly, and the page looks fine when I view the local copy in Firefox. There are no specific styles attached to the image.

I have the Webmaster add-on, and when I select "View Generated Source," the HTML shows an added class for the image:

<img class=" qjqlmlhmpphlzrcnieeg"