WP save attachment with AJAX

admin-custom-image-page.php

<div id="tmx-image" data-img="<?php echo wp_get_attachment_url( $_GET['attachment_id'] );	?>">
		</div>

<script>
  var tmx_img  = $('#tmx-image').data('img');
  
  $('#tmx-save').on('click',function(){
			Caman("#tmx-image",tmx-image, function () {
        // this = formatted image using Caman JS for example
			  var new_image = this.toBase64();
				$('#tmx-loader').show();

        //save To Server
        var data = {
          'action': 'tmx_save_image',
          'old_image': tmx_img,
          'new_image': new_image,
        };

        // since 2.8 ajaxurl is always defined in the admin header and points to admin-ajax.php
        $.post(ajaxurl, data, function(response) {
          if("error" != response ){
            window.location = response;
          }
          else {
            alert('Image not saved!');
          }
        });
        
			});
		});
</script>

wp-attachment-image-save.php

<?php

// Run the action at 'admin_init'
add_action( 'admin_init', array( $this, 'init' ) );

public function init(){
	// Hook another action, so we can call it from JS
	add_action('wp_ajax_tmx_save_image', array( $this,'easy_image_filters_save_image_ajax_callback') );
}

public function wp_ajax_tmx_save_image_ajax_callback() {
		$uploads       = wp_upload_dir();
		$filetype_info = wp_check_filetype( $_POST['old_image'] );
		$file_type     = $filetype_info['type'];
		$file_ext      = $filetype_info['ext'];
	
		// Easy, send the new image in POST['new_image'] in Base64 format
		$data          = base64_decode(preg_replace('#^data:image/\w+;base64,#i', '', $_POST['new_image']));
		$filename      = basename( $_POST['old_image'] );
		$filename      = wp_unique_filename( $uploads['path'], $filename );
		$saved_file    = file_put_contents($uploads['path'] . "/" .$filename, $data);

		$attachment = array(
			'post_mime_type' => $file_type,
			'post_title' => preg_replace('/\.[^.]+$/', '', $filename),
			'post_content' => '',
			'post_status' => 'inherit',
			'guid' => $uploads['url'] . "/" .$filename
		);

		$attach_id = wp_insert_attachment( $attachment, $uploads['url'] . "/" . $filename, 0 );
		require_once(ABSPATH . "wp-admin" . '/includes/image.php');
		$attach_data = wp_generate_attachment_metadata( $attach_id, $uploads['path'] . "/" . $filename );
		$success = wp_update_attachment_metadata( $attach_id,  $attach_data );

		if( $success ){
			echo add_query_arg( 'item', $attach_id, admin_url('upload.php') );
		}else{
			echo 'error';
		}

		exit(0);

	}