title: Linux batch (gimp, imagemagick) add background image to series of transparent pngs
body: <p>is it possible to add a different background image to a series of transparent pngs?</p>
  
  <p>Like:  convert sourceimage.png -background BackgroundPicture -flatten destinationimage.png</p>
  
  <p>Of course the background image should be lowered to bottom of the frames.</p>
  
  <p>Thanks in advance</p>