The point is to get a completely processed image

My friends. Many years have passed and you have not implemented a single method for obtaining a processed image. Probably when the bundle was first created, you relied on the template engine and the URL addresses of the images in the templates. Today, most websites and applications operate on API principles. The existing functionality does not allow you to simply receive a processed image.

You have something like this createFilteredBinary function - in reality, you need a function that returns the imageBinary based on the parameters ($path, $filter) The point is to get a completely processed image given $config['default_image'] with saving to cache if it is not there exactly as it does createFilteredBinary function but return imageBinary

Start by locating the existing createFilteredBinary function and tracing how it handles $path, $filter, $config['default_image'], and cache storage. Clarify the public entry point and expected binary result, then verify that a processed image is returned and cached when absent, matching the existing function's behavior.