Insert images into a pdf using the pdf doc from template node

Good morning,

We have to generate a pdf from a given template (we are using the pdf doc from template node), this template will be filled with text fields that we get from the database but we also have to attach a loaded signature to the end of the pdf in an image that we obtain previously.
But we were not able to load it inside any of the tags that the template has, we have tried to mount the two pdfs separately and then do a merge but this would not work for us because as I mentioned we need the image to be in one of the template fields.
Has anyone had this same problem?

Greetings and thank you