Note: Instructions are based on the default “TwentyTen” Theme
(default size is 940×198)
1- Open your file “functions.php” in a text editor
(will be located in your theme)
2- Find the following code:
define( ‘HEADER_IMAGE_HEIGHT’, apply_filters( ‘twentyten_header_image_height’, 198 ) );
3- Change “198” to your desired size
4– SAVE AND OVERWRITE YOUR PREVIOUS functions.php FILE
5- Re-upload your 198 pixel height banner / header
Continue reading WordPress Theme: How to change the header banner height?