Fix uppercase type of image in OPC UA
diff --git a/documentation/html/communication/opc_ua_version1.html b/documentation/html/communication/opc_ua_version1.html
index d63765b..04e9043 100644
--- a/documentation/html/communication/opc_ua_version1.html
+++ b/documentation/html/communication/opc_ua_version1.html
@@ -405,7 +405,7 @@
<ol>
<li>We add the <span class="element4diac">SUBSCRIBE</span> function block called SUBCRIPTION. The SUBSCRIBE function block gets the updated value automatically without a need to actively trigger the RSP event.</li>
<li>The application now looks like this:
- <div><img src="../../html/communication/img/opc_ua_subscriptions_2.PNG" alt="OPC UA Subscription Application"/></div>
+ <div><img src="../../html/communication/img/opc_ua_subscriptions_2.png" alt="OPC UA Subscription Application"/></div>
</li>
<li>Note, that the <span class="element4diac">RD_1</span> port of the <span class="element4diac">SUBSCRIBE</span> is the current value of the subscribed node. Additionaly, you need to make sure that the data type of the <span class="element4diac">RD</span> port matches the types from the OPC UA variable you want to subscribe to. Use the corresponding <span class="element4diac">conv</span> FBs for that, as shown in this example.</li>
<li>Deploy the Application to FORTE</li>
