custom file browser

I am interested in a Windows Explorer type browser that would apply images to customer filetypes as a thumbnail. For example, if I had a file [login to view URL], and in the same folder a file test.ibm.png...this would show in the browser as [login to view URL] with a thumbnail using the PNG of the same name. A configuration file to define the filetypes that need this would be good,, and just typical explorer functionality for files not defined.