There is actually quite a lot broken with the folder templates and customisation within Windows XP. Apparently, this was due to it being incorrectly programmed by teenaged interns (though I can't say whether or not this was true, it makes sense enough to me.)
There is no way to add a new template, but it is possible to achieve a similar effect by first assigning a folder to a particular template, then altering the specifics within the registry.
You need to identify the particular folder after changing it to one of the existing templates within the registry:
[Whatever] will be any number
There is a
REG_SZ string Value named
FolderType for the TEMPLATE type to use:
i.e. "MyMusic" for Music, "MyPictures" for images, "Documents" for 'Documents of any type'
The text for these is located within the "%WINDIR%/shell.inf" file
REG_SZ String Value contains the Class ID for the "watermark" image. At this time, I cannot comment on what filetypes are valid, but bmp, gif, png or jpg should all be attempted.