diff --git a/tools/aapt/Images.cpp b/tools/aapt/Images.cpp
index 9939c18..cc26b4f 100644
--- a/tools/aapt/Images.cpp
+++ b/tools/aapt/Images.cpp
@@ -833,6 +833,7 @@
         bpp = 4;
     } else {
         printf("Unknown color type %d.\n", color_type);
+        return;
     }
 
     for (j = 0; j < h; j++) {