This page is obsolete. I am no longer using header images, since I found they used up too much of the page and distracted so much from the content that it was sometimes not always evident that a new page had been chosen.
However, someone else may choose to use header images when creating their own WordPress site, using perhaps the instructions I give on a new website about creating and using such sites.
Here is the old contents of this page:
One reason I like to have multiple WordPress installations is to keep all related pages and posts in a common layout, under a common header image. For example, my main website about Social Technology has hundreds of posts. When someone views any one of them, they will see a page which looks like this:
The same page layout will be seen no matter what the content of any particular post of page on that site. I think this a great advantage. Therefore I have created multiple WordPress installations, each with its own page layout. Most noticeably, each page or post will be shown beneath a common header images. Here are various header images I have created in various ways. You may click on the images to view them full size, which for the twenty ten theme I prefer is 940 by 198.
The main SocialTechnology.ca site has a header image clipped from a public domain image taken from the WikiMedia Commons:
I think using a carefully chosen piece of artwork does make for a prettier page. In this case I chose a social situation, the most a propos I could find for a website about society. Elsewhere I have added material of my own to an existing image, to make a pretty and reasonably effective header. In the following example, for a short online novel set in Africa, I used an African village scene, into which I inset a couple of faces, those of the lead characters. As appropriate for fiction, these are not real people, but morphs made by combining images of different individuals.
Elsewhere I have taken a photo myself and cropped it for use as a header image. In this case I was creating a website about books I have written or can recommend, so I took a photo of one of my bookshelves.
A more recent website, about the romantic aspects of social technology was made by just adding a border, background texture and large-font text to a blank image of the right size for a website header.
These are but a few examples of header images I’ve created and used for websites. My basic rule is to have a unique header image for each site, even if nothing else about the page layout is different. Other examples of header images can be seen in this post.