Bloom and background images

Hi, I’ve a background image (I put the image as background using hints I found in the forums), but, when I activate the bloom effect it disappears. Is it the expected behavior or am I doing something wrong? This is the code to reproduce it. Very thanks!

from direct.gui.OnscreenImage import OnscreenImage
import direct.directbase.DirectStart
base.cam2dp.node().getDisplayRegion( 0 ).setSort( -20 )
OnscreenImage( parent = base.cam2dp, image = 'maps/envir-ground.jpg' )
# if I remove the comments below then the image disappears
# from direct.filter.CommonFilters import CommonFilters
# CommonFilters(, ).setBloom()