I want to place a tracking pixel in a specific Xenforo template. The pixel is in the form: PHP: <?phpecho ("<img src=\"https://blahblahblah.com/?variable1=12345&variable2=54321&variable3=98765\" width=\"1\" height=\"1\">");?> From what I have read, I need to do this using an XenForo callback. I have read some documentation on this but I am unsure about it all. Is it just a matter of creating a php file with the above code and then calling it from the template? Does the file have to be placed in a specific folder?