my $mask = Image::Magick->new;
my $background = Image::Magick->new;
my $foreground = Image::Magick->new;

$mask->Read("mask.png");

$background->Set(size=>'500x500');
$background->Read("xc:white");

$foreground->Read("foreground.jpg");

$background->Composite(compose=>'Dissolve', opacity => '87.8', image=>$foreground); 
$background->Composite(image=>$mask);
$background->Write("output.jpg");