how extends form validation with custom file check validation?

You are trying to access $_FILES['file'] instead of $_FILES['picture']. But just try to return false, to see if it's working or not.

And please remove xss_clean from everywhere, it's not supposed to be used:
https://codeigniter.com/userguide3/insta...ation-rule

Hi @jreklund , thanks for the answer; I already tried to change file by image and I still don't get the validation message, just by returning false

I don't know what else to try