diff --git a/src/common.h b/src/common.h
index 87ec8a7..5c8e0d1 100644
--- a/src/common.h
+++ b/src/common.h
@@ -22,6 +22,7 @@ void dprintf(const char *fmt, ...);
 
 /* available CAPTCHA decoders */
 char *decode_phpbb(struct image *img);
+char *decode_scode(struct image *img);
 char *decode_slashdot(struct image *img);
 char *decode_test(struct image *img);
 
@@ -37,6 +38,7 @@ int setpixel(struct image *img, int x, int y, int r, int g, int b);
 /* image filters */
 void filter_flood_fill(struct image *img, int x, int y, int r, int g, int b);
 struct image *filter_fill_holes(struct image *img);
+struct image *filter_dup(struct image *img);
 struct image *filter_detect_lines(struct image *img);
 struct image *filter_equalize(struct image *img, int threshold);
 struct image *filter_trick(struct image *img);
diff --git a/src/filters.c b/src/filters.c
index 44501d3..126ad05 100644
--- a/src/filters.c
+++ b/src/filters.c
@@ -52,6 +52,24 @@ void filter_flood_fill(struct image *img, int x, int y, int r, int g, int b)
         filter_flood_fill(img, x, y - 1, r, g, b);
 }
 
+struct image *filter_dup(struct image *img)
+{
+    struct image *dst;
+    int x, y;
+    int r, g, b;
+
+    dst = image_new(img->width, img->height);
+
+    for(y = 0; y < img->height; y++)
+        for(x = 0; x < img->width; x++)
+        {
+            getpixel(img, x, y, &r, &g, &b);
+            setpixel(dst, x, y, r, g, b);
+        }
+
+    return dst;
+}
+
 struct image *filter_fill_holes(struct image *img)
 {
     struct image *dst;