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On your way in you may have missed that we have a
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As to your question, the javadocs for ImageIO.read(InputStream) state that "If no registered ImageReader claims to be able to read the resulting stream, null is returned." It also states "This methods does not attempt to locate ImageReaders that can read directly from an InputStream; that may be accomplished using IIORegistry and ImageReaderSpi." That's slightly different from what ImageIO.read(File) does. What kind of image is this?