diff --git a/Libs/lpng163/pngrutil.c b/Libs/lpng163/pngrutil.c
index a4fa714..486ac56 100644
--- a/Libs/lpng163/pngrutil.c
+++ b/Libs/lpng163/pngrutil.c
@@ -3158,10 +3158,13 @@ png_check_chunk_length(png_const_structrp png_ptr, const png_uint_32 length)
    else
    {
       size_t row_factor =
-         (png_ptr->width * png_ptr->channels * (png_ptr->bit_depth > 8? 2: 1)
-          + 1 + (png_ptr->interlaced? 6: 0));
+         (size_t)png_ptr->width
+         * (size_t)png_ptr->channels
+         * (png_ptr->bit_depth > 8? 2: 1)
+         + 1
+         + (png_ptr->interlaced? 6: 0);
       if (png_ptr->height > PNG_UINT_32_MAX/row_factor)
-         limit=PNG_UINT_31_MAX;
+         limit = PNG_UINT_31_MAX;
       else
          limit = png_ptr->height * row_factor;
       limit += 6 + 5*(limit/32566+1); /* zlib+deflate overhead */