LOAD_FILE() works on SELECT, but returns NULL on insert
LOAD_FILE, only reads the contents from the file and returns the contents from itself as a string, you try to add an image into field and using this function isn't gonna be possible. Besides you should have FILE privilege to you could do this and allocating the file into /var/lib/mysql-files. Being this a bad practice, the best is add the route relative or absolute from this file.