you can create an image and rename it and upload it to themes directory. it would be something like this: yourwordpressdirectory/themes/mx4_theme/images/kubrickheader.jpg
as for the second part, i would not do what xtool suggests, because this will mess things up if you use the Blogs of the Day plugin. it relies on that title for linking purposes. According to binarybonsai, which mx4 is based of kubric, “The best way of doing this, is to open wp-layout.css. Find the first entries you can find for ‘H1’ and ‘.description’. Now add ‘display: none;’ to the values in there.”