In the recent redesign, the basic design has been separated into four components:

1. TGenerator – The thumbnail generating class.
2. TImageParams – A container for parameters such as image size and source files which is the basic unit which is processed by TGenerator
3. TRunner – A management class which holds and creates TImageParams objects to handoff to TGenerator.
4. THelper – A helper class which provides convenience methods to generate thumbnails through TGenerator without using TRunner or TImageParams.

TGenerator continues to use the Java Image I/O API, and it is written for Java 2 SE Platform 1.4. Rather than using the ImageIO convenience methods for reading and writing images, the new Thumbnailator uses the ImageReader and ImageWriter classes which provide more flexible options for I/O, such as allowing the specification of compression quality.