Image not showing up (firefox adding strange class?)

I can't seem to figure out why, but on occasion, when I put an image onto a page, Firefox add a random strange class and hides the image. I run the same page in Chrome, and no issue.

The class its adding is " uhqmzxrrksmvdmnsqyuu" but as far as I can tell, that's not consistent. In the past, simply moving the file to another folder has fixed the issue, but its getting pretty frustrating.

Anyone have any thoughts as to what's going on?

Anyone have any thoughts as to what's going on?
You might have "Ad block plus" installed on your FF and its filters might be blocking the path/name of your image.

Interesting... never considered Ad Block working against me.. :P

I'll give it a shot and let you know what happens.

Of course it was ABP... thanks :)