[Solved] Problem with image resize codeigniter

You need to verify your $file_name variable a bit more. I think your error is being invoked by an empty filename.

PHP Code:

if (!empty($file_name) &&  !file_exists(FCPATH . 'uploads/cache/' . $file_name)) { 


And as @ivantcholakov says, properly validate your input, make shure it does not contain a '/'