GetFileUrl From aspx/cs file?

I'm using a direct uploader property on a page type, and when looking at the stored value it's a guid. How do you get the files URL from that guid?

I've found this: http://devnet.kentico.com/docs/8_2/api/html/M_CMS_Controls_TransformationHelper_GetFileUrl_1.htm

But that requires a file name as well ass a guid. Is there a media object namespace I should be using? The file will always be an image if that helps.