Yes, it's about the same effect as on your site, altough you don't have to add the image tag to all descriptions, just upload images with the correct name. It's also possible to put the image in different places, it doesn't have to be in the description.
I'm not sure that I follow you on the last question... This hack only changes the front page, so if you go to a board it will be the same as before. I do have another hack that I haven't released which will allow you to put board specific information above the board name on the postlist page.
