JEITA  CP-3451 - 17 - A.    Tags relating to image data structure ImageWidth The number of columns of image data, equal to the number of pixels per row. In JPEG compressed data a JPEG marker is used instead of this tag.   Tag = 256 (100.H) Type = SHORT or LONG Count = 1 Default = none ImageLength The number of rows of image data. In JPEG compressed data a JPEG marker is used instead of this tag. Tag = 257 (101.H) Type = SHORT or LONG Count = 1 Default = none BitsPerSample The number of bits per image component. In this standard each component of the image is 8 bits, so the value for this tag is 8. See also SamplesPerPixel. In JPEG compressed data a JPEG marker is used instead of this tag. Tag = 258 (102.H) Type = SHORT Count = 3 Default = 8    8    8 Compression The compression scheme used for the image data. When a primary image is JPEG compressed, this designation is not necessary and is omitted. When thumbnails use JPEG compression, this tag value is set to 6. Tag = 259 (103.H) Type = SHORT Count = 1 Default = none 1 = uncompressed 6 = JPEG compression (thumbnails only) Other = reserved PhotometricInterpretation The pixel composition. In JPEG compressed data a JPEG marker is used instead of this tag. Tag = 262 (106.H) Type = SHORT Count = 1 Default = none 2 = RGB 6 = YCbCr Other = reserved