shades [-data location] [picture]
Shades can be passed two kinds of information via command line parameters - picture file to open at startup and data location.
Data means the files stored by Shades: option (config) file and background pictures. There are three possible kinds of values. First, and most intuitive, is folder - simply pass as "location" path, the inside should handle it ... almost always.
The other two are to be used mostly for debugging and troubleshooting purposes. They start with @ and can be "@registry" or, shortly "@reg" which means the values will be fetched from registry, and "@none" - you guessed it, no data are loaded from outside. At this time, both of these disable background changes, which is not a big loss, as you would not be able to load any backgrounds anyway. The registry mode fully preserves all data.
Path to picture which should be loaded. The path can be both absolute and relative. The only change is that wrong slashes are replaced with correct type.
If the file is not found or picture cannot be loaded, Shades start as if nothing was passed.