public List<String> getChunkTypes(final InputStream is) throws ImagingException, IOException {
        final List<PngChunk> chunks = readChunks(is, null, false);
        final List<String> chunkTypes = Allocator.arrayList(chunks.size());
        for (final PngChunk chunk : chunks) {
            chunkTypes.add(getChunkTypeName(chunk.getChunkType()));
        }
        return chunkTypes;
    }
@param is PNG image input stream
@return List of String-formatted chunk types, ie. "tRNs".
@throws ImagingException if it fail to read the PNG chunks
@throws IOException      if it fails to read the input stream data
src/main/java/org/apache/commons/imaging/formats/png/PngImageParser.java