Inserting code into the_content

Hi everybody

I’d like to add a Facebook-like button into my posts. My site ( https://www.hanskfroschauer.com ) is kind of a photoblog, so there’s always a large image and then some text beneath that.

I’d like to insert this button between the image and the text, but my theme calls the_content and I can’t seem to figure out how to edit the content of the_content (excuse the pun) – isn’t that possible? Isn’t there a place where I can edit what goes into the_content, and how it’s displayed?

I searched the forum, and obviously Google, but to no avail. In short, what I want to do is to put a div underneath the image (but above the text) on every single-post-page.

Thank for your help.