The only thing about Firefox that annoys me....

Why is there not an option for a toolbar button that with a single click 
will download the images for the currently viewed page? This should not 
refresh, just fetch and fill in the missing images (avoiding duplicated 
download and allowing it to work with "Captcha" web pages, refresh often 
resets everything).

Like many people in rural areas I depend on comparatively expensive 
Mobile Internet with a very restrictive usage policy.
I also often have to use modestly powered computers ( i.e netbooks). So, 
90% of my browsing is done with "Load pictures automatically" unchecked. 
However, when I finally reach the page I am interested in I then have to 
change the preferences turning it on and then refresh, go back into 
preferences and turn it back off. This becomes very tedious after 20 
minutes of browsing.