It's been my experience that Firefox is great for most Internet uses, and great at saving usernames and passwords and remembering info like that. But it is painfully slow with saving images. From the very act of right-clicking the image, the slooooow speed is immediately apparent. It continues as I have to wait 30 whole seconds or more for the "save as" screen to pop up. I choose the right place, hit okay, and wait for about 1 or 2 minutes for the thing to save and then let me navigate the site again. I thought for a long time it was just my computer, but Opera saves images about as fast as one could snap. I think Firefox will be my general web-surfing browser, and the instant I want even one picture, I will copy the link over to Opera to save it from there.
EDIT: Okay, so I just counted. I can save 30 images using Opera in the time it takes to save one image with Firefox.