As standard format for regular images the following data formats for memory-efficient storage have been established:

• lossy
  • GIF (quantization to palette)
  • JPEG (DCT = discrete cosine transformation)
  • JPEG2000 (wavelets)
• lossless
  • TIFF, PNG, ZLIB
  • PPM → netppm library [1]

Beside the raw image data those formats store none to little meta data

• PNG, TIFF: gamma
• GEOTIFF: GPS tags
• EXIF standard: GPS positions and capture settings of digital photos
• etc.

For medical data patient information needs to be documented:

• patient name, birthday, age and id
• date of acquisition
• metric resolution
• doctor commentary and diagnosis
• diagnosis follows standardized workflow with numerous steps that need to be documented

Also: Lossy compression is considered harmful due to potential misinterpretation.

To account for the medical requirements, there is a standardized format for medical imagery: DICOM.