diff --git a/contrib/libtests/pngstest.c b/contrib/libtests/pngstest.c
index 996c87153..56ad96a65 100644
--- a/contrib/libtests/pngstest.c
+++ b/contrib/libtests/pngstest.c
@@ -3209,7 +3209,11 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
       {
          /* This is non-fatal: */
          if (size > PNG_IMAGE_PNG_SIZE_MAX(image->image))
+         {
             logerror(image, "memory", ": PNG_IMAGE_SIZE_MAX wrong", "");
+            if ((image->opts & STRICT) != 0)
+               return 0;
+         }
 
          initimage(output, image->opts, "memory", image->stride_extra);
          output->input_memory = malloc(size);
@@ -3224,7 +3228,12 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
             {
                /* This is also non-fatal (maybe): */
                if (size != output->input_memory_size)
+               {
                   logerror(image, "memory", ": memory size wrong", "");
+
+                  if ((image->opts & STRICT) != 0)
+                     return 0;
+               }
             }
 
             else
diff --git a/png.h b/png.h
index e98b475ff..23d76bc60 100644
--- a/png.h
+++ b/png.h
@@ -3142,8 +3142,9 @@ PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
 #define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
    ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
     (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
-     12U+PNG_IMAGE_COLORMAP_SIZE(image)/*PLTE+tRNS data*/+\
-     (((image).format&PNG_FORMAT_FLAG_ALPHA)?12U/*tRNS*/:0U):0U)+\
+     12U+3U*(image).colormap_entries/*PLTE data*/+\
+     (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
+      12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
     12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
    /* A helper for the following macro; if your compiler cannot handle the
     * following macro use this one with the result of