Linking products in Sub-folders of Download folder to atttributes

I'm selling Downloadable products only.

When I set up the attribute for a product to link the download, I have sub-folders in my download folder (product types), so what is the path I want to use to link the files:

"/sub_folder_name/product.zip" or "sub_folder_name/product.zip" Do I need the "/" in the path name first or not?

Thanks! :dontgetit:

You do not need the leading / for a sub-directory-located file (e.g. mysubdir/myzip.zip). The value that you record as the download file's name is appended to the value present in the DIR_FS_DOWNLOAD constant, which has a trailing /.

Does it matter if some have it and some don't? Should I make them all uniform?

Also, I thought I saw an area in Admin where I could select allowable File Types and I cannot find it now. I have PNG files on my products. Are PNG files not allowed to be downloaded? I had a customer (new store) end up with a 403 Forbidden Error. Must I zip up all files? (My PNG files are very small, one item only - I thought it would be easier on my customers to only have to download them quickly.