If you’re using WordPress for your blog, you’re no doubt familiar with the default theme, Kubrick, with the big blue box header:
Blog Header Generator — If you’d like to keep that theme but use one of your own photographs as a background, try this easy tool from fd’s Flickr Toys collection. You can upload a photograph from your PC, or choose one from your Flickr photostream or from another URL, click on Create, and you’ll get back the image you need, cropped, sized and ready for use.
Note that this is not just a header image, but the background image for the whole page, and that it must include the gray background and white borders to work correctly in this theme. Once you have the image file, you’ll need to FTP it to your themes directory, where the default background image lives, for example:
Here are a few examples of photographs used as backgrounds for the WordPress default theme:
Note that most photographs will need substantial cropping for this theme. The tool will perform the cropping for you, but will only provide you with limited control over how the image is cropped. By default, for example, it just takes the center. For more control over the image, you may want to crop photographs manually first to reduce them to the right general proportions, about 722 pixels wide by 183 pixels high.