Forum:How come the images aren't showing up?

I am trying to contribute to this wikia by adding images and such, but when I type in the image name in some of the articles (such as 'Owl', 'White Owl', and 'Animal Float') it still shows up as a red question mark. Why is this and is it my fault i'm doing it incorrectly? For example, on the White Owl article I put this: "|Image    = owl2" and owl2.jpg is the image file. Shouldn't this work?

Also, does anyone know what I need to do to get very good resulting pictures such as? And how could I make the white around images transparent? Sorry for all of these hassling questions...