What are transaction descriptors?
{"Image Make": "Canon", "Image Model": "Canon EOS 5D Mark IV", "Image Orientation": "Horizontal (normal)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CC 2018 (Windows)", "Image DateTime": "2018:04:29 23:40:58", "Image ExifOffset": "220", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "894", "Thumbnail JPEGInterchangeFormatLength": "3967", "EXIF ExposureTime": "1/100", "EXIF FNumber": "9/2", "EXIF ExposureProgram": "Manual", "EXIF ISOSpeedRatings": "250", "EXIF SensitivityType": "Recommended Exposure Index", "EXIF RecommendedExposureIndex": "250", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2018:04:14 15:11:08", "EXIF DateTimeDigitized": "2018:04:14 15:11:08", "EXIF ShutterSpeedValue": "415241/62500", "EXIF ApertureValue": "86797/20000", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "1", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "35", "EXIF SubSecTime": "00", "EXIF SubSecTimeOriginal": "00", "EXIF SubSecTimeDigitized": "00", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "2720", "EXIF ExifImageLength": "1813", "EXIF FocalPlaneXResolution": "61166933/32768", "EXIF FocalPlaneYResolution": "61166933/32768", "EXIF FocalPlaneResolutionUnit": "3", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Manual Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF BodySerialNumber": "155056000736", "EXIF LensSpecification": "[35, 35, 0/0, 0/0]", "EXIF LensModel": "35mm", "EXIF LensSerialNumber": "0000000000"}