[onion2k]

Does the canvas need to be created and removed as it comes in and out of view?

Not really. You could just create them and not bother removing them. You'd need to check if the user already had an avatar if you did that though, or you'd end up with lots of repeated avatars when you scroll up and down the page.

[dncornholio]

Or just generate them on page load and call it a day. No bugs, no complexity, no edge cases.

Could it be faster? Sure, but should it be faster? Not really, IMO, the avatars load very quick, even on a big page.