What's the right progress for uploading image using image intervention library

Need you know, the spesification is:

*/ Server using Nginx. */ Framework Laravel 5.1. */ Image Intervention Library. */ Retrofit android API RestClient library.

When I uploading a image with size <1mb it's working right. But if the image >1mb file, I getting error 502 Bad Gateway (Using Postman). If I using my android apps, file with <1mb I get response 200(OK), but if file with >1mb I can't retrive anything response code.

This is my php code with image intervention library:

public function move_uploaded_to_tmp($file){
        //render name
        $name = $this->render_name();
        $ori_ext = $file->getClientOriginalExtension();
        //move to tmp storage
        $file->move($this->tmp_directory, "{$name}.{$ori_ext}");
        return $name.'.'.$ori_ext;
    }

    public function handle_tmp_img($filename){
        $file_tmp = Storage::get('tmp'.DIRECTORY_SEPARATOR.$filename);
        $alias_name = $this->render_name(); // ini alias name untuk thumbnail directory
        $image = Image::make($file_tmp);
        // encode image to png
        $image->encode($this->ext_file);
        // save original
        $image->save($this->original_directory.$filename.'.'.$this->ext_file);
        //resize
        $image->resize(300,300);
        // save resized
        $image->save($this->thumbnail_directory.$alias_name.'.'.$this->ext_file);
        $img->destroy();
        // delete tmp file
        @unlink($this->tmp_directory.$filename);
        return $alias_name;
    }

When I disable $image->save(); it's not return error but file just created in tmp folder(cannot created to oroginal and thumbnail folder)..

via Chebli Mohamed