Maybe simplify by using 2 different words. One for producing a daily chart and one for a monthly one. This way, you just have to deal with one additional input: The ticker. Seems easier for everybody, IMHO.
Should it do that, maybe try to produce the replacement text as a link between [img] BBCode tags or markdown tags, if that’s possible. I guess it should and this may force the system to treat it as an image if it doesn’t do it on its own (unless it will display it as text). You indeed have to try it. Please post the results here
You seem to have gone in a wrong direction with this, Robert.
This was what you mentioned in a previous message too, now deleted.
If you copy the example link from the first post of this topic and paste it into a message, you’ll see it directly shows as an image just fine. OP’s goal is more about a way of producing these links easily for his forum users, if I understood correctly. Of course the links also need to be processed the same way as when you insert them manually in a post.