[Mooff]

I was talking about the stylevars: imgdir_statusicon / imgdir_misc / imgdir_button / imgdir_siteicons /
Stylevars where our addon needs to read the old files. The files which are displayed when our addon is not running. The files which shall be replaced by our addon.

Of course we cannot connect to an external server to write the sprite. So imgdir_sprite has to be local - which is stated as an error via the addon.

edit: TMS is not needed. You can do all template changes manually. But i would strongly advise to use TMS, since the number of changes is really high. TMS does them in a blink of an eye. Manually does take it's time though.
As a sidenote. If vb4 would have native sprite support, no user based template changes would be necessary at all.