Lucy, You can click on these thumbnails for a larger version. Depending on your browser, you may be able to click again to view the full size file. As you can see, there is a lot more blue than the images on your website. I have done nothing to these images other than convert them to jpegs. This did not affect the color at all. Are these accurate representations of the originals? The backgrounds of the images on your website are much lighter (whiter).
Lucy, This is just an example to try and show you what I mean by "removing the background." IMO - it is a much classier look when the design blends in with the shirt, as opposed to the look of a print or photo "pasted" on the shirt. And this is not always easy to accomplish depending on the existing background. Click for larger version.