Removed the `throws IOException` and annotated the javadoc with information about when to use the `iterableBufferedImages` method.
Removed the `throws IOException` and annotated the javadoc with information about when to use the `iterableBufferedImages` method.

guhb/thumbnailator,giflw/thumbnailator,coobird/thumbnailator,qingsong-xu/thumbnailator,ymero/thumbnailator