let uri = Components.classes["@mozilla.org/network/io-service;1"].getService(Components.interfaces.nsIIOService).newURI(_("color-image").value, null, null);
if (uri instanceof Components.interfaces.nsIFileURL && uri.file instanceof Components.interfaces.nsILocalFile)
{
filePicker.displayDirectory = uri.file.parent;
}
}
catch (ex) { /* no valid (file) URI, so no default directory to set */ }