How costly is loading an image with a JavaScript?

I have been thinking about this for quite some time and thought I should ask the question here .

Let us take the case of a spinner . A spinner can be shown using javascript and CSS3 . However we can just simply load a spinner.gif using javascript and be done with it . To me it looks like, in a distributed code (Java EE Application), the image will have to be retrieved from the server every time and hence it will be more costly . Is my assumption correct ? Are there any more posts which experts know of here that has already compared these 2 processes ?