The images are centered vertically in the slideshow’s container with the ‘top: 50%;
‘ CSS value. This will place the top of the button image in the center, but leaves the rest of the button below the center. The ‘margin-top: -20px;
‘ pulls the button up half its height so it’s completely centered.
If you want to have buttons from top to bottom, you should do something like this:
.slideshow_container_0 .slideshow_button {
top: 0; /* Brings the buttons to the top. */
height: 100%; /* I'm not sure whether or not this works in all versions of Internet Explorer. */
width: 100px; /* Any width you'd like. */
background: url('URL to your image') no-repeat;
}
If you’re using the default image, you should probably use something like CSS background-position as well.