diff --git a/src/gd_jpeg.c b/src/gd_jpeg.c
index 744f229..271ef46 100644
--- a/src/gd_jpeg.c
+++ b/src/gd_jpeg.c
@@ -108,7 +108,7 @@ static void fatal_jpeg_error(j_common_ptr cinfo)
 	char buffer[JMSG_LENGTH_MAX];
 
 	(*cinfo->err->format_message)(cinfo, buffer);
-	gd_error_ex(GD_ERROR, "gd-jpeg: JPEG library reports unrecoverable error: %s", buffer);
+	gd_error_ex(GD_WARNING, "gd-jpeg: JPEG library reports unrecoverable error: %s", buffer);
 
 	jmpbufw = (jmpbuf_wrapper *)cinfo->client_data;
 	jpeg_destroy(cinfo);
diff --git a/src/gd_png.c b/src/gd_png.c
index db8de72..9dca659 100644
--- a/src/gd_png.c
+++ b/src/gd_png.c
@@ -68,7 +68,7 @@ gdPngErrorHandler (png_structp png_ptr, png_const_charp msg)
 	 * regardless of whether _BSD_SOURCE or anything else has (or has not)
 	 * been defined. */
 
-	gd_error_ex(GD_ERROR, "gd-png: fatal libpng error: %s\n", msg);
+	gd_error_ex(GD_WARNING, "gd-png: fatal libpng error: %s\n", msg);
 
 	jmpbuf_ptr = png_get_error_ptr (png_ptr);
 	if (jmpbuf_ptr == NULL) {				/* we are completely hosed now */
diff --git a/tests/jpeg/.gitignore b/tests/jpeg/.gitignore
index 06cc9b2..c28aa87 100644
--- a/tests/jpeg/.gitignore
+++ b/tests/jpeg/.gitignore
@@ -1,3 +1,4 @@
+/bug00338
 /bug_github_18
 /jpeg_empty_file
 /jpeg_im2im
diff --git a/tests/jpeg/CMakeLists.txt b/tests/jpeg/CMakeLists.txt
index e8ecf63..04d6483 100644
--- a/tests/jpeg/CMakeLists.txt
+++ b/tests/jpeg/CMakeLists.txt
@@ -5,6 +5,7 @@ LIST(APPEND TESTS_FILES
 	jpeg_read
 	jpeg_empty_file
 	jpeg_resolution
+	bug00338
 	bug_github_18
 )
 ENDIF(JPEG_FOUND)
diff --git a/tests/jpeg/Makemodule.am b/tests/jpeg/Makemodule.am
index bc196b1..d09f9c5 100644
--- a/tests/jpeg/Makemodule.am
+++ b/tests/jpeg/Makemodule.am
@@ -7,6 +7,7 @@ libgd_test_programs += \
 
 if HAVE_LIBPNG
 libgd_test_programs += \
+	jpeg/bug00338 \
 	jpeg/jpeg_read \
 	jpeg/jpeg_resolution
 endif
diff --git a/tests/jpeg/bug00338.c b/tests/jpeg/bug00338.c
new file mode 100644
index 0000000..92c55a9
--- /dev/null
+++ b/tests/jpeg/bug00338.c
@@ -0,0 +1,51 @@
+/**
+ * Regression test for <https://github.com/libgd/libgd/issues/338>
+ *
+ * We're testing that reading a PNG image with gdImageCreateFromJpeg()
+ * raises a GD_WARNING for the fatal libjpeg error, but not a GD_ERROR.
+ * We also make sure, that the fatal libjpeg error is actually reported.
+ *
+ * See also ../png/bug00338.c
+ */
+
+
+#include <string.h>
+#include "gd.h"
+#include "gd_errors.h"
+#include "gdtest.h"
+
+
+#define MSG "gd-jpeg: JPEG library reports unrecoverable error: %s"
+
+
+static int error_handler_called = 0;
+
+
+static void error_handler(int priority, const char *format, va_list args)
+{
+    if (!strcmp(format, MSG)) {
+        gdTestAssertMsg(priority == GD_WARNING, "expected priority %d, but got %d", GD_WARNING, priority);
+        error_handler_called = 1;
+    }
+}
+
+
+int main()
+{
+    gdImagePtr im;
+    FILE *fp;
+
+    gdSetErrorMethod(error_handler);
+
+    im = gdImageCreateTrueColor(10, 10);
+    fp = gdTestTempFp();
+    gdImagePng(im, fp);
+    gdImageDestroy(im);
+
+    im = gdImageCreateFromJpeg(fp);
+    gdTestAssert(im == NULL);
+
+    gdTestAssert(error_handler_called);
+
+    return gdNumFailures();
+}
diff --git a/tests/png/.gitignore b/tests/png/.gitignore
index 28eb412..97972c1 100644
--- a/tests/png/.gitignore
+++ b/tests/png/.gitignore
@@ -3,6 +3,7 @@
 /bug00086
 /bug00088
 /bug00193
+/bug00338
 /png_im2im
 /png_null
 /png_resolution
diff --git a/tests/png/CMakeLists.txt b/tests/png/CMakeLists.txt
index 228474e..a577a67 100644
--- a/tests/png/CMakeLists.txt
+++ b/tests/png/CMakeLists.txt
@@ -8,6 +8,7 @@ LIST(APPEND TESTS_FILES
 	bug00086
 	bug00088
 	bug00193
+	bug00338
 )
 ENDIF(PNG_FOUND)
 
diff --git a/tests/png/Makemodule.am b/tests/png/Makemodule.am
index 01c4803..7e73dd6 100644
--- a/tests/png/Makemodule.am
+++ b/tests/png/Makemodule.am
@@ -5,6 +5,7 @@ libgd_test_programs += \
 	png/bug00086 \
 	png/bug00088 \
 	png/bug00193 \
+	png/bug00338 \
 	png/png_im2im \
 	png/png_null \
 	png/png_resolution
diff --git a/tests/png/bug00338.c b/tests/png/bug00338.c
new file mode 100644
index 0000000..af16df1
--- /dev/null
+++ b/tests/png/bug00338.c
@@ -0,0 +1,48 @@
+/**
+ * Regression test for <https://github.com/libgd/libgd/issues/338>
+ *
+ * We're testing that writing a PNG image with an unsupported quality
+ * raises a GD_WARNING for the fatal libpng error, but not a GD_ERROR.
+ * We also make sure, that the fatal libpng error is actually reported.
+ *
+ * See also ../jpeg/bug00338.c
+ */
+
+
+#include <string.h>
+#include "gd.h"
+#include "gd_errors.h"
+#include "gdtest.h"
+
+
+#define MSG "gd-png: fatal libpng error: %s\n"
+
+
+static int error_handler_called = 0;
+
+
+static void error_handler(int priority, const char *format, va_list args)
+{
+    if (!strcmp(format, MSG)) {
+        gdTestAssertMsg(priority == GD_WARNING, "expected priority %d, but got %d", GD_WARNING, priority);
+        error_handler_called = 1;
+    }
+}
+
+
+int main()
+{
+    gdImagePtr im;
+    FILE *fp;
+
+    gdSetErrorMethod(error_handler);
+
+    im = gdImageCreateTrueColor(10, 10);
+    fp = gdTestTempFp();
+    gdImagePngEx(im, fp, 100);
+    gdImageDestroy(im);
+
+    gdTestAssert(error_handler_called);
+
+    return gdNumFailures();
+}