IGMDTAG_NAME_PNG_FORMAT             "PNG"
IGMDTAG_NAME_PNG_RESOLUTION         "pHYs"
IGMDTAG_NAME_PNG_HEADER             "IHDR"
IGMDTAG_NAME_PNG_TRANSPARENCY       "tRNS"
IGMDTAG_NAME_PNG_GAMMA              "gAMA"
IGMDTAG_NAME_PNG_CHROMATICITIES     "cHRM"
IGMDTAG_NAME_PNG_SRGB               "sRGB"
IGMDTAG_NAME_PNG_ICC_PROFILE        "iCCP"
IGMDTAG_NAME_PNG_BACKGROUND         "bKGD" 
IGMDTAG_NAME_PNG_SIGNIFICANT_BITS   "sBIT"
IGMDTAG_NAME_PNG_SUGGESTED_PALETTE  "sPLT" 
IGMDTAG_NAME_PNG_HISTOGRAM          "hIST"
IGMDTAG_NAME_PNG_TIME               "tIME"
IGMDTAG_NAME_PNG_TEXT               "tEXt"
IGMDTAG_NAME_PNG_COMPRESSED_TEXT    "zTXt"
IGMDTAG_NAME_PNG_INTERNATIONAL_TEXT "iTXt" 
IGMDTAG_NAME_PNG_CALIBRATION        "pCAL" 
IGMDTAG_NAME_PNG_PHYSICAL_SCALE     "sCAL" 
IGMDTAG_NAME_PNG_GIF_APP_EXT        "gIFx"    
IGMDTAG_NAME_PNG_GIF_CONTROL        "gIFg"  
IGMDTAG_NAME_PNG_IMAGE_OFFSET       "oFFs"  
IGMDTAG_NAME_PNG_FRACTAL_PARAMETERS "fRAc"   
IGMDTAG_NAME_PNG_GIF_TEXT_EXT       "gIFt" 
IGMDTAG_NAME_PNG_IHDR_WIDTH         "Width"
IGMDTAG_NAME_PNG_IHDR_HEIGHT        "Height"
IGMDTAG_NAME_PNG_IHDR_BIT_DEPTH      "BitDepth"
IGMDTAG_NAME_PNG_IHDR_COLOR_TYPE     "ColorType"
IGMDTAG_NAME_PNG_IHDR_COMPRESSION    "CompressionType"
IGMDTAG_NAME_PNG_IHDR_FILTER_TYPE    "FilterType"
IGMDTAG_NAME_PNG_IHDR_INTERLACE_TYPE "InterlaceType"
IGMDTAG_NAME_PNG_PHYS_X_AXIS         "XAxis"
IGMDTAG_NAME_PNG_PHYS_Y_AXIS         "YAxis"
IGMDTAG_NAME_PNG_PHYS_UNIT           "UnitSpecifier"
IGMDTAG_NAME_PNG_ICCP_NAME           "ProfileName"
IGMDTAG_NAME_PNG_ICCP_DATA           "ProfileData"
IGMDTAG_NAME_PNG_CHRM_WHITE          "WhitePoint"
IGMDTAG_NAME_PNG_CHRM_RED            "Red"
IGMDTAG_NAME_PNG_CHRM_GREEN          "Green"
IGMDTAG_NAME_PNG_CHRM_BLUE           "Blue"
IGMDTAG_NAME_PNG_CHRM_X              "x"
IGMDTAG_NAME_PNG_CHRM_Y              "y"
IGMDTAG_NAME_PNG_TEXT_KEYWORD        "Keyword"
IGMDTAG_NAME_PNG_TEXT_TEXT           "Text"
IGMDTAG_NAME_PNG_CTXT_KEYWORD        "Keyword"
IGMDTAG_NAME_PNG_CTXT_COMPR_METHOD   "CompressionMethod"
IGMDTAG_NAME_PNG_CTXT_TEXT           "Text"
IGMDTAG_NAME_PNG_ITXT_KEYWORD        "Keyword"
IGMDTAG_NAME_PNG_ITXT_COMPR_FLAG     "CompressionFlag"
IGMDTAG_NAME_PNG_ITXT_COMPR_METHOD   "CompressionMethod"
IGMDTAG_NAME_PNG_ITXT_LANGUAGE       "LanguageTag"
IGMDTAG_NAME_PNG_ITXT_TRANSL_KEYWORD "TranslatedKeyword"
IGMDTAG_NAME_PNG_ITXT_TEXT           "Text"
IGMDTAG_NAME_PNG_SPLT_NAME          "PaletteName"
IGMDTAG_NAME_PNG_SPLT_DEPTH         "SampleDepth"
IGMDTAG_NAME_PNG_SPLT_ENTRY_COUNT   "PaletteEntryCount"
IGMDTAG_NAME_PNG_SPLT_ENTRY         "PaletteEntry"
IGMDTAG_NAME_PNG_SPLT_RED           "Red"
IGMDTAG_NAME_PNG_SPLT_GREEN         "Green"
IGMDTAG_NAME_PNG_SPLT_BLUE          "Blue"
IGMDTAG_NAME_PNG_SPLT_ALPHA         "Alpha"
IGMDTAG_NAME_PNG_SPLT_FREQUENCY     "Frequency"
IGMDTAG_NAME_PNG_TIME_YEAR          "Year"
IGMDTAG_NAME_PNG_TIME_MONTH         "Month"
IGMDTAG_NAME_PNG_TIME_DAY           "Day"
IGMDTAG_NAME_PNG_TIME_HOUR          "Hour"
IGMDTAG_NAME_PNG_TIME_MINUTE        "Minute"
IGMDTAG_NAME_PNG_TIME_SECOND        "Second"
IGMDTAG_NAME_PNG_OFFS_X_POSITION    "XPosition"
IGMDTAG_NAME_PNG_OFFS_Y_POSITION    "YPosition"
IGMDTAG_NAME_PNG_OFFS_UNIT          "UnitSpecifier"
IGMDTAG_NAME_PNG_PCAL_NAME          "CalibrationName"
IGMDTAG_NAME_PNG_PCAL_X0            "OriginalZero(x0)"
IGMDTAG_NAME_PNG_PCAL_X1            "OriginalMax(x1)"
IGMDTAG_NAME_PNG_PCAL_EQUATION      "EquationType"
IGMDTAG_NAME_PNG_PCAL_PAR_COUNT     "NumberOfParameters"
IGMDTAG_NAME_PNG_PCAL_UNIT          "UnitName"
IGMDTAG_NAME_PNG_PCAL_PARAMETER     "CalibrationParameter"
IGMDTAG_NAME_PNG_SCAL_UNIT          "UnitSpecifier"
IGMDTAG_NAME_PNG_SCAL_WIDTH         "PixelWidth"
IGMDTAG_NAME_PNG_SCAL_HEIGHT          "PixelHeigt"
IGMDTAG_NAME_PNG_GIFG_DISPOSAL_METHOD "DisposalMethod"
IGMDTAG_NAME_PNG_GIFG_USER_INPUT_FLAG "UserInputFlag"
IGMDTAG_NAME_PNG_GIFG_DELAY_TIME      "DelayTime"
IGMDTAG_NAME_PNG_GIFX_APP_ID          "ApplicationIdentifier"
IGMDTAG_NAME_PNG_GIFX_AUTHENTICATION  "AuthenticationCode"
IGMDTAG_NAME_PNG_GIFX_APP_DATA        "ApplicationData"
 IGMDTAG_ID_PNG_FORMAT                 = IG_FORMAT_PNG,
 IGMDTAG_ID_PNG_HEADER                 = 0x49484452,
 IGMDTAG_ID_PNG_TRANSPARENCY           = 0x74524e53,
 IGMDTAG_ID_PNG_GAMMA                  = 0x67414d41,
 IGMDTAG_ID_PNG_CHROMATICITIES         = 0x6348524d,
 IGMDTAG_ID_PNG_SRGB                   = 0x73524742,
 IGMDTAG_ID_PNG_ICC_PROFILE            = 0x69434350,
 IGMDTAG_ID_PNG_BACKGROUND             = 0x624b4744,
 IGMDTAG_ID_PNG_SIGNIFICANT_BITS       = 0x73424954,
 IGMDTAG_ID_PNG_SUGGESTED_PALETTE      = 0x73504c54,
 IGMDTAG_ID_PNG_HISTOGRAM              = 0x68495354,
 IGMDTAG_ID_PNG_TIME                   = 0x74494d45,
 IGMDTAG_ID_PNG_TEXT                   = 0x74455874,
 IGMDTAG_ID_PNG_COMPRESSED_TEXT        = 0x7a545874,
 IGMDTAG_ID_PNG_INTERNATIONAL_TEXT     = 0x69545874,
 IGMDTAG_ID_PNG_CALIBRATION            = 0x7043414c,
 IGMDTAG_ID_PNG_PHYSICAL_SCALE         = 0x7343414c,
 IGMDTAG_ID_PNG_GIF_APP_EXT            = 0x67494678,
 IGMDTAG_ID_PNG_GIF_CONTROL            = 0x67494667,
 IGMDTAG_ID_PNG_IMAGE_OFFSET           = 0x6f464673,
 IGMDTAG_ID_PNG_FRACTAL_PARAMETERS     = 0x66524163,
 IGMDTAG_ID_PNG_GIF_TEXT_EXT           = 0x67494674,
 IGMDTAG_ID_PNG_RESOLUTION             = 0x70485973