The tutorial discusses how to optimize images in PHP using the Intervention Image package. The application allows users to upload an image, compress it, and save it in a different format with reduced quality. The author explains that there are two key ways to optimize images: choosing the best file format and using image compression. They discuss various image formats such as PNG, JPEG, GIF, SVG, AVIF, and WebP, highlighting their characteristics and use cases. The tutorial also covers lossy and lossless compression methods, which can affect the quality of the compressed image.