“absmiddle” is a non-standard value for an images tags align property.
While widely implemented, it isn’t a part of the HTML 4.x spec.

This helpful property caused the image to be shifted down to rest on the same line as elements around it.

Example of image without align property

Image button without the align property set.

Image button with proper alignment.

Here is a CSS way to make an image have the same settings as the absmiddle property.

IMG.absmiddle {
vertical-align: middle;
margin-bottom: .25em;

Thanks to George on code2design.com for this tip.