diff --git a/converters/frompnm.c b/converters/frompnm.c
index 8e8b758c..2253ffad 100644
--- a/converters/frompnm.c
+++ b/converters/frompnm.c
@@ -24,7 +24,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <ctype.h>
-#include <assert.h>
+#include <sixel.h>
 
 
 static unsigned char *
@@ -55,7 +55,7 @@ unsigned char *
 load_pnm(unsigned char *p, int length,
          int *psx, int *psy, int *pcomp,
          unsigned char **ppalette, int *pncolors,
-         int *pixelformat)
+         int *ppixelformat)
 {
     int n, i, b, x, y, component[3];
     int ascii, maps;
@@ -65,7 +65,6 @@ load_pnm(unsigned char *p, int length,
 
     (void) ppalette;
     (void) pncolors;
-    (void) pixelformat;
 
     width = height = 0;
     deps = 1;
@@ -213,6 +212,7 @@ load_pnm(unsigned char *p, int length,
 
     *psx = width;
     *psy = height;
+    *ppixelformat = PIXELFORMAT_RGB888;
     return result;
 }
 
diff --git a/converters/frompnm.h b/converters/frompnm.h
index 9464f32d..ff85a35a 100644
--- a/converters/frompnm.h
+++ b/converters/frompnm.h
@@ -34,7 +34,7 @@ unsigned char *
 load_pnm(unsigned char *p, int len,
          int *psx, int *psy, int *pcomp,
          unsigned char **ppalette, int *pncolors,
-         int pixelformat);
+         int *ppixelformat);
 
 #ifdef __cplusplus
 }
diff --git a/converters/loader.c b/converters/loader.c
index 73107854..eb0cd982 100644
--- a/converters/loader.c
+++ b/converters/loader.c
@@ -643,7 +643,6 @@ load_with_builtin(chunk_t const *pchunk, int *psx, int *psy,
     static stbi__gif g;
     chunk_t frames;
     chunk_t delays;
-    int pixelformat = PIXELFORMAT_RGB888;
 
     if (chunk_is_sixel(pchunk)) {
         pixels = load_sixel(pchunk->buffer, pchunk->size,
@@ -658,7 +657,7 @@ load_with_builtin(chunk_t const *pchunk, int *psx, int *psy,
     } else if (chunk_is_pnm(pchunk)) {
         /* pnm */
         pixels = load_pnm(pchunk->buffer, pchunk->size,
-                          psx, psy, pcomp, ppalette, pncolors, pixelformat);
+                          psx, psy, pcomp, ppalette, pncolors, ppixelformat);
         if (!pixels) {
 #if HAVE_ERRNO_H
             fprintf(stderr, "load_pnm failed.\n" "reason: %s.\n",