My favored theme for WordPress is the NeoClassical Theme developed by Chris Person. Not only do I like his use of white space and fonts, but my personal favorite is the header. Here's why.
Chris incorporated an easy to use random image header. The server load is low because the image is only updated once each time a page is loaded. There is no changing of the picture while you are trying to read.
More importantly, to update the header, simply download images labeled header_1.jpg, header_2.jpg, etc. into the images directory for the theme. Then we have to adjust one file random.php in the theme. We adjust the number of images and voila! We get random images on each web page of the site.
Note that the images should be 865 pixels wide by 180 pixels high. Black and white or color work fine. Thanks, Chris! ... Read More!
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