diff --git a/core/test/src/com/google/zxing/common/AbstractBlackBoxTestCase.java b/core/test/src/com/google/zxing/common/AbstractBlackBoxTestCase.java
index 2be51a675..e996a565e 100644
--- a/core/test/src/com/google/zxing/common/AbstractBlackBoxTestCase.java
+++ b/core/test/src/com/google/zxing/common/AbstractBlackBoxTestCase.java
@@ -114,7 +114,7 @@ public abstract class AbstractBlackBoxTestCase extends Assert {
   }
 
   protected final File[] getImageFiles() {
-    assertTrue("Please run from the 'core' directory", testBase.exists());
+    assertTrue("Please download and install test images, and run from the 'core' directory", testBase.exists());
     return testBase.listFiles(IMAGE_NAME_FILTER);
   }
 
diff --git a/core/test/src/com/google/zxing/qrcode/QRCodeWriterTestCase.java b/core/test/src/com/google/zxing/qrcode/QRCodeWriterTestCase.java
index 98b5cfd23..a5d9739ce 100644
--- a/core/test/src/com/google/zxing/qrcode/QRCodeWriterTestCase.java
+++ b/core/test/src/com/google/zxing/qrcode/QRCodeWriterTestCase.java
@@ -45,7 +45,7 @@ public final class QRCodeWriterTestCase extends Assert {
       // try starting with 'core' since the test base is often given as the project root
       file = new File("core/" + BASE_IMAGE_PATH + fileName);
     }
-    assertTrue("Please run from the 'core' directory", file.exists());
+    assertTrue("Please download and install test images, and run from the 'core' directory", file.exists());
     return ImageIO.read(file);
   }