Adjusting Feature Banner Dimensions?

[gimmeputtgolf 0]

Hi guys, Using the feature banners in full width format, however need to adjust the height of an uploaded banner to approximately 250px (I've uploaded a banner 960x250) but it still occupies the old dimensions. How do we adjust the size of space used? Is it via CSS?

[bryan-hadaway 3]

I better get a link to the page in question so I can understand/test it better. Thanks, Bryan