You can draw semitransparent PNG images: open it as '??? with alpha', loading image to picture and alpha-channel to clipboard, or manually draw image on picture and alpha-channel in clipboard (image and alpha-channel must have same horis. and vert. sizes), switch between editing of image/alpha-channel with '0'-'Alpha'-'Picture<->CB', render your semitransparent image on different backgrounds with '0'-'Alpha'-'Render alpha', save your image with alpha-channel from clipboard after selection 'Alpha in Clipboard' during PNG saving.