https://pharo.manuscript.com/f/cases/21611
With the new File/Stream changes in Pharo 7, ImageReadWriter and subclasses broke because these classes are not yet capable of working with simple binary streams.
I created a new test case (attached) to catch the functional degradation. For each image type (class) there are 2 tests, IO in memory and IO to file.
I have a bunch of changes that make all tests pass. They clean up some strange coding as well.
I will make a proper PR later.