Changing the header images
    in the WordPress 2011 theme,
          by substituting them with your own.

I've tried various ways of changing the header images in the
WordPress 2011 theme. I found out that you need to replace them
with images which are identical in size (and name also) …

If you have a look at the screenshot above, you will see that there
are two sizes for each photo … in fact there are 8 different photos,
making 16 images in all to substitute with your own photos.

The dimensions are 1000 x 288 pixels for the header images,
& 230 x 66 pixels for the thumbnail images.

The sizes in kilobytes range from 38-93 KB (mean: 60 KB) for the
headers and 3.68-8.17 KB (mean: abt. 5 KB for the thumbnails.

You will need to retain the same titles for the headers and
thumbnails, so for example, you should create new images
entitled “hanoi.jpg” and “hanoi-thumbnail.jpg” … all in lower case.

The images rotate in random order when viewed on a webpage
online, so if you don't have enough suitable photos ready, you
could use say 4 photos, using one of them to replace both      
“chessboard” and “hanoi” temporarily, and another one to replace
“lanterns” and “pine-cone”, etc..

Creating a new header image

You will need to use or do the following in Gimp (see my Gimp page 1
or use Photoshop) … the Crop tool, scaling your image down in size,
keyboard shortcuts for copy & paste, and the Move tool.

1. create two yellow folders on your Desktop, one entitled say:
   “old wp images” and the second as “new wp images” for your
   replacements.

2. Create one blank white canvas, 1000 x 288 px

3. Do a rough selection of your header image from one of your
   prized photos with the Crop tool.

4. Scale the width of your selection down to 1000px. Hopefully
   the height value will be slightly above 288px, as you will now
   use the Crop tool to edge the height slowly down to 288px or
   more likely 287px. Use the “Undo History” box to go back in
   time, if you over-crop the image.
   So you've now got a header image most likely at 1000 x 287px.

5. If the image is exactly 1000 x 288px, you can now save the
   image (Shift + Ctrl + E) using one of the titles: such as
   “hanoi.jpg”. Save it probably at about 90% quality to reduce
   the end-kilobyte size down to less than 100 KB. You might
   have to re-save the image at a lower percentage quality to
   lower the overall size.
   
   You can now create the thumbnail image, by scaling it down
   in Gimp to 230 x 66 px. Save the thumbnail as above, with
   the title say as “hanoi-thumbnail.jpg”.
   
   If your header image is at 1000 x 287px, which is likely, you
   will need to copy and paste it onto the white canvas you've
   created above.
   
   Select the header image … Ctrl + A.
   Copy it … Ctrl + C
   Paste it onto the white canvas … Ctrl + V
   Use the Move tool to re-position the image on the white
   canvas, if it's a fair bit smaller than the canvas.
   Flatten the two layers to one layer 
                … Layer (on top toolbar) > Flatten image
   Remove the “marching ants” … Shift + Ctrl + A
   (or Select > None)
   Save the image as above.
   Re-size it down to thumbnail size, and save this as above.
   Put all your new images into the new folder: “new wp headers”
   Here's an example of one of my letter-box photos, which
   I've re-named as pine-cone.jpg
   (I've reduced the image size, to fit it into this webspace)
   .

6. The next task will be to get all your new images posted online, which 
   I go into on the next webpage ... click on "Next" below.