Problem with the ImageUtils class

We are using the class ImageUtils for our import project. One remark, there are two different ImageUtils classes in the code base.

The class itself has a memory problem. The Readers are cached in a static map. Problem with these readers is that they keep a reference to the actual byte[]. I also do not see a very good reason to cache these readers. The memory problem becomes visible with bigger files, but each type keeps a lot of memory. To give you an idea, we had a picture of 8Mb that took over 300 Mb of memory.

I am also wondering why the thumbnail method returns the byte[] of the original image if something goes wrong, why not throw an exception. The same thing for obtaining specific readers. Why return null and not an exception?

I made a fix, that made the class more readable. Beware I removed all the static stuff. Maybe you can use it for a change. Most urgent is the memory problem stuff.