You said my suggestion on the other forum worked ok for the PDF??
Not clear what else you are attempting but I have just answered there and will repeat:
My procedure, fwiw, is to right click the item and select properties, and then "change icon". If I am not satisified with the shown default selection, then there are choices. You can browse through the (system32) dlls, or select the main source, which is C:\Windows\System32\imageres.dll-
Another alternative is to download one of the free icon packages, such as
Free Icons Web - Icons, Free Icons, Stock Icons, Desktop Icon
to a folder, and browse there for something suitable.