Thank you so much guys. It looks like it's finally working. The biggest problem was obviously my complete lack of knowledge and trying to send to url through as a string rather than JSON. So now it works from an inject node, and I have managed to get it to work from a dropdown menu (we will have around 20 odd pictures we need to choose from), but I wonder if there's a simpler method...
The dropdown menu only seems to allow a string boolean or number, so I have the url set as a string, and then a change node to change the msg.payload from a string to a JSON, but I have to put the url for each image in the search and replace fields. Is there something I can enter to just search "whatever text" and replace it with the same?
