diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4d2705f..b39e0ec 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,7 +17,7 @@ jobs:
     - name: Update Build Environment
       run: sudo apt-get update --fix-missing -y
     - name: Install Prerequisites
-      run: sudo apt-get install -y cppcheck zlib1g-dev
+      run: sudo apt-get install -y cppcheck zlib1g-dev libpng16-dev
     - name: Configure PDFio
       run: ./configure --enable-debug --enable-sanitizer --enable-maintainer
     - name: Build PDFio
diff --git a/testpdfio.c b/testpdfio.c
index a8da015..562b65e 100644
--- a/testpdfio.c
+++ b/testpdfio.c
@@ -3088,7 +3088,6 @@ write_png_tests(pdfio_file_t *pdf,	// I - PDF file
   else
     return (1);
 
-#ifdef HAVE_LIBPNG
   ////// PDFio PNG image test page...
   // Create the page dictionary, object, and stream...
   fputs("pdfioDictCreate: ", stdout);
@@ -3235,6 +3234,7 @@ write_png_tests(pdfio_file_t *pdf,	// I - PDF file
   else
     return (1);
 
+#ifdef HAVE_LIBPNG
   ////// PngSuite page
   // Create the image objects...
   for (i = 0; i < (sizeof(pngsuite_files) / sizeof(pngsuite_files[0])); i ++)