i chose this extension because it's the only one i found to use kenburns without flash.
Sadly, like i noticed nearly a month ago already, the kenburns is almost impossible to use as it is so much ressource hungry.
may it be on firefox or chrome, on a brand new site, so not bloated, it uses between 30 and 50% of my cpu on a clean, new computer. (dual core 8 gig ram)
and on older computers, it uses almost 100% of cpu.
so for kenburns effects, there's no way to use it at all (i found none actually)