diff --git a/Tests/test_file_webp.py b/Tests/test_file_webp.py
index a86757e64..4a048f2c2 100644
--- a/Tests/test_file_webp.py
+++ b/Tests/test_file_webp.py
@@ -164,7 +164,7 @@ class TestFileWebp:
         with pytest.raises(ValueError) as e:
             im.save(temp_file)
         assert (
-            str(e.value) == "encoding error 5: Image size exceeds WebP limit of 16383"
+            str(e.value) == "encoding error 5: Image size exceeds WebP limit of 16383 pixels"
         )
 
     def test_WebPEncode_with_invalid_args(self) -> None:
diff --git a/src/_webp.c b/src/_webp.c
index c0e1a6f63..b4cf9c329 100644
--- a/src/_webp.c
+++ b/src/_webp.c
@@ -676,7 +676,7 @@ WebPEncode_wrapper(PyObject *self, PyObject *args) {
         char message[50] = "";
         if (error_code == VP8_ENC_ERROR_BAD_DIMENSION) {
             sprintf(
-                message, ": Image size exceeds WebP limit of %d", WEBP_MAX_DIMENSION
+                message, ": Image size exceeds WebP limit of %d pixels", WEBP_MAX_DIMENSION
             );
         }
         PyErr_Format(PyExc_ValueError, "encoding error %d%s", error_code, message);