Make php file use laravel (outside controller)

Web text editor (ckeditor) inside my app uses a php file (with ajax) for loading images inside a folder. Inside that php file I cannot use Laravel functions (like DB or User), which I would really need.

My question is, is there a way to make a php file inside the project, but outside a controller use Laravel functions? The path to my file is .../public/... and not .../app/..., will that make things difficult?

via Chebli Mohamed