What is Proper way to create Thumbnail

If you don't want the "_thumb" part adding to the file name include the parameter create_thumb => false like this:

Code:

 $config=array(
           'image_library'=>'gd2',
            'source_image' => $image_data['full_path'],  /*Original Image*/
            'create_thumb'=>FALSE,
            'new_image' =>'./uploads/thumbs',
            'maintain_ratio'=>TRUE,
            'width' => 150,
            'height' => 150
        );