diff --git a/f3discovery/src/10-serial-communication/README.md b/f3discovery/src/10-serial-communication/README.md
index 10149fe4c..7a982855e 100644
--- a/f3discovery/src/10-serial-communication/README.md
+++ b/f3discovery/src/10-serial-communication/README.md
@@ -2,7 +2,7 @@
 
 <a href="https://en.wikipedia.org/wiki/File:Serial_port.jpg">
 <p align="center">
-<img height="240" title="Standard serial port connector DE-9" src="https://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Serial_port.jpg/800px-Serial_port.jpg">
+<img height="240" title="Standard serial port connector DE-9" src="https://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Serial_port.jpg/960px-Serial_port.jpg">
 </p>
 </a>
 
diff --git a/microbit/src/06-serial-communication/README.md b/microbit/src/06-serial-communication/README.md
index 8714b7df4..d0d5db6b6 100644
--- a/microbit/src/06-serial-communication/README.md
+++ b/microbit/src/06-serial-communication/README.md
@@ -2,7 +2,7 @@
 
 <a href="https://en.wikipedia.org/wiki/File:Serial_port.jpg">
 <p align="center">
-<img height="240" title="Standard serial port connector DE-9" src="https://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Serial_port.jpg/800px-Serial_port.jpg">
+<img height="240" title="Standard serial port connector DE-9" src="https://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Serial_port.jpg/960px-Serial_port.jpg">
 </p>
 </a>