diff -u gif2png-2.3.0/gif2png.c ./gif2png.c
--- gif2png-2.3.0/gif2png.c	Sat Dec  4 14:43:34 1999
+++ ./gif2png.c	Sat Jan 22 00:53:12 2000
@@ -19,6 +19,7 @@
 
 struct GIFelement first={NULL};
 struct GIFelement *current;
+FILE *overlay = NULL;
 int delete = FALSE;
 int optimize = FALSE;
 int histogram = FALSE;
@@ -35,6 +36,19 @@
 long numgifs = 0L;
 long numpngs = 0L;
 
+int get_next_overlay_bit(void)
+{
+    static int overlay_mask = 0;
+    static int overlay_value = 0;
+
+    if (!(overlay_mask >>= 1)) {
+        overlay_value = fgetc(overlay);
+	if (overlay_value < 0)
+	    return -1;
+	overlay_mask = 128;
+    }
+    return (overlay_value & overlay_mask)? 1:0;
+}
 
 int interlace_line(int height, int line)
 /* return the actual line # used to store an interlaced line */
@@ -197,6 +211,7 @@
     if (last_color<16) bitdepth = 4;
     if (last_color<4) bitdepth = 2;
     if (last_color<2) bitdepth = 1;
+    if (overlay) bitdepth = 8;
 
     if (gray) {
 	remapping = TRUE;
@@ -264,6 +279,16 @@
 	}
     }
 
+    if (overlay && last_color >127) {
+	fprintf(stderr, "gif2png:  too many colors\n");
+	free(png_ptr);
+	free(info_ptr);
+	return 1;
+    } else {
+        colors_used *= 2;
+	last_color += last_color+1;
+    }
+
     if (verbose > 1)
 	fprintf(stderr, "gif2png: %d colors used, highest color %d, %s, bitdepth %d\n",
 		colors_used, last_color, gray ? "gray":"palette", bitdepth);
@@ -391,12 +416,27 @@
 		pal_rgb[i].blue  = current->imagestruct->colors[remap[i]].blue;
 	    }
 	    info_ptr->palette = pal_rgb;
-	} else {
+	} else if (overlay) {
+	    if (verbose > 2)
+		fprintf(stderr, "Making two copies of the Palette...\n");
+	    for (i = 0; i <= last_color; i++) {
+		pal_rgb[i].red   = current->imagestruct->colors[i].red;
+		pal_rgb[i].green = current->imagestruct->colors[i].green;
+		pal_rgb[i].blue  = current->imagestruct->colors[i].blue;
+		pal_rgb[i + last_color + 1].red   = current->imagestruct->colors[i].red;
+		pal_rgb[i + last_color + 1].green = current->imagestruct->colors[i].green;
+		pal_rgb[i + last_color + 1].blue  = current->imagestruct->colors[i].blue;
+	    }
+	    info_ptr->palette = pal_rgb;
+        } else {
 	    if (verbose > 2)
 		fprintf(stderr, "Palette copied from GIF colors...\n");
 	    info_ptr->palette = current->imagestruct->colors;
 	}
-	info_ptr->num_palette = last_color+1;
+	if (overlay)
+	    info_ptr->num_palette = 2*(last_color+1);
+	else
+	    info_ptr->num_palette = last_color+1;
 	info_ptr->valid |= PNG_INFO_PLTE;
 
 	if (verbose > 2) {
@@ -491,6 +531,12 @@
 				data[j] = remap[data[j]];
 			    }
 			}
+		    if (overlay) {
+			    for (j = 0; j < img->width; j++) {
+				if (get_next_overlay_bit())
+				    data[j] += last_color + 1;
+			    }
+			}
 		    png_write_row(png_ptr, data);
 		}
 	    break;
@@ -814,6 +860,21 @@
 		webconvert = TRUE;
 		break;
 
+            case 'o':
+		if (ac >= argc - 1)
+		{
+		    fputs("gif2png: missing background-matte argument\n",
+			  stderr);
+		    exit(1);
+		}
+		overlay = fopen(argv[++ac], "rb");
+		if (!overlay){
+		    fputs("gif2png: unable to open overlay file\n",
+			  stderr);
+		    exit(1);
+		}
+		goto skiparg;
+
 	    case 'O':
 		optimize = TRUE;
 		break;
@@ -831,6 +892,7 @@
 	"   -h  generate PNG histogram chunks into color output files\n"
 	"   -i  force conversion to interlaced PNG files\n"
 	"   -n  force conversion to noninterlaced PNG files\n"
+	"   -o  overlay file\n"
 	"   -p  display progress of PNG writing in %%\n"
 	"   -r  try to recover corrupted GIF files\n"
 	"   -s  do not write Software text chunk\n"
@@ -890,6 +952,9 @@
 	    }
 	}
     }
+
+    if (overlay && get_next_overlay_bit() >= 0)
+	fprintf(stderr, "Not enough image data to hold the overlay.\n");
 
     if (verbose)
 	fprintf(stderr, "Done (%s).  Converted %ld GIF%s into %ld PNG%s.\n",