for transparency in sysmetrix, you need to save it with transparent areas in 'magic pink' , which is rgb 255,0,255

if you want to add translucent areas, such as a shadow, etc., you can use a workaround wich is supported in the newer versions of sysmetrix: u create a background file that is all white, then you create another png file that is going to be ur real background wich has your translucent parts (this will be actual transparency, not magic pink). then, under sysmetrix configuration>theme settings> and check copy desktop background for pseudotransparency option. then create a graphics object and use ur .png as the file, and render graphic before everything else.