Add screenshots for printing labels via the app

docs/app/stock.md

@@ -150,6 +150,18 @@ Select the *assign barcode* action to scan this third-party barcode and assign i
 
 This barcode can then be used to track the stock item.
 
+#### Print Label
+
+If the server supports [label printing plugins](../extend/plugins/label.md), then an option to print a label for the selected stock item:
+
+{% with id="label_print_1", url="app/stock_print_label_1.png", description="Print label via plugin" %}
+{% include 'app_img.html' %}
+{% endwith %}
+
+{% with id="label_print_2", url="app/stock_print_label_2", description="Print label via plugin" %}
+{% include 'app_img.html' %}
+{% endwith %}
+
 ### Edit Stock Item
 
 To edit the stock item details, select the *Edit* button in the top right corner of the screen: