After switching from Chrome (the Chrome extension) to Firefox (the Firefox extension) there have been a few pros and cons. I've noticed that for sites that ask for a specific file type, the extension would not load on Chrome, but does on Firefox. Nice. However, when the upload dialog appears, the screen for some reason shifts to the bottom of the page, which is very annoying especially for long pages. Also, a feature that I've wanted since I've used the extension during my time using Chrome, was to not have the popup appear if there is no images/files copied. Thank you!

Works well in Zen Browser