Needing help with logos and headers.

I’m just getting familiar with Mantra, and had a question.

I’m creating a custom logo using photoshop, although im able to upload a header image, I don’t see the a logo anywhere when I upload one of those. Also the header image doesn’t cover the entire header even if I max out the dimensions when I upload it. There’s a little strip on the bottom of the header (where the page links are) that doesn’t get covered by header images I upload.

So I have 3 questions all related to making my website look nice…

First question… Where does a logo go when I upload it and select it? I don’t see it in the header or anywhere else, are there any do’s or dont’s with logos?

Second question… Similar the first, but in relation to the header image, How do I get an image to cover the entire header? Do I have to shrink the header with to fit the image? I’d rather not have to, and Im trying to work with images which would be thick enough to cover the entire header.

Third question… This one is crucial, because if I can get it to work it would increase the flexibility of the themes appearence by a lot. I’m wondering if there is a way to place an image ANYWHERE I want, say if I wanted to put an image in the header in a particular spot, or if I wanted to put it in the middle of the page, or in the footer, and be able to tweek it’s location from left to right.

I’ll use CSS coding for this if I have to (if it’s possible) but as of now I don’t have any experience with it, if the ability to put images anywhere is not a part of the theme, is there a plugin I could use to accomplish this? (keep in mind that by image, I don’t mean a photo that will be part of a gallery, it’ll be strictly decoration)

Thanks in advance for any help 🙂