the problem is, it just cuts parts of the image it rotates. If you rotate left a part of the image is just gone. It should be centered and then you can see the whole picture.

Almost perfect. When the image is rotated to the left, you can't see a big part of the image, the scrollbar isn't adjusted to the rotated image.

PS: The problem occurs in any direction because the image is anchored in the center.

Great addon, does not require intrusive permissions (unlike "Rotate and Zoom Image").

It would be possible to rotate images at google classroom? (you know, activities sent by students)

works fine for me. Note that it only rotates in 90 degrees increments not arbitrary angles.
It offers 'left', 'right', 'flip' and 'reset'