commit de0a9fca47409cd4b69feee5895eb97b00877ac9
Author: Dan Gildea <dgildea>
Date:   Sat Dec 1 09:35:05 2018 -0500

    ppmtopng syntax works with all versions of ppmtopng

diff --git a/Changes b/Changes
index 21986b4..f7a0e43 100644
--- a/Changes
+++ b/Changes
@@ -112,6 +112,7 @@
 # A more detailed log history can be found within the particular files, near
 # the top.
 #
+#		- ppmtopng syntax works with all versions of ppmtopng
 #		- respect ./configure --with-perl=/bin/perl
 #		- fallback for unknown column types, such as those
 #		  introduced by \newcolumntype.
diff --git a/latex2html.pin b/latex2html.pin
index 69a2bdf..010658c 100755
--- a/latex2html.pin
+++ b/latex2html.pin
@@ -4259,9 +4259,13 @@ sub extract_image_bitmap { # clean
         if ($name =~ /equation|eqnarray|display/){
             $imgpixeloverex *= $DISP_SCALE_FACTOR if $DISP_SCALE_FACTOR}
         my $millimeter=int(.04*$DVIPNG_DPI); 
-        $TRANSPARENT_COLOR='FFFFFF' unless defined $TRANSPARENT_COLOR;
-        if ($TRANSPARENT_COLOR){$transparent= "-transparent='#$TRANSPARENT_COLOR'"}
-        else{$transparent =''}
+        if ($TRANSPARENT_FIGURES) {
+	    my $TRANSPARENT_COLOR=
+		$ENV{'TRANSPARENT_COLOR'} || '#FFFFFF';
+	    $transparent= "-transparent '$TRANSPARENT_COLOR'";
+	} else {
+	    $transparent ='';
+	}
         my $PPMTO=$IMAGE_TYPE=~m/gif/i? $PPMTOGIF : $PNMTOPNG;
         #L2hos->syswait("$PNGTOPNM $p.png|$PNMCROP -sides|tee $p.ppm|$PNMCUT -top $millimeter |$PNMCROP -sides|tee $p-.ppm|$PPMTO{$IMAGE_TYPE} --quiet $transparent >img$new_num.$IMAGE_TYPE;");
         if ($name =~ /figure|table/) {
