Ghost in the Shell: Firefox might hate your .tiff file

While Safari and Google Chrome don't mind, Firefox might not like to show your .tiff file.  Avoid using .tiff files and instead use

.jpg

.gif

and

.png

filetypes. Firefox seems to digest these just fine.  Don't be fooled by the fact that you can indeed upload a .tiff file while using Wordpress in Firefox. When you get to the site, your image won't be there!