Classes for loading/saving images:
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    - BMP (Win + OS/2)      load (1) save (1)
    - C64 (Koala, Doodle)   load (2)
    - Degas (PI1, PI2, PI3) load (3)
    - FBM                   load (1) save (1)
    - GIF (87a/89a)         load (2) save (2)
    - IFF-ILBM              load (1) save (1)
    - IMG (HS16/HS18)       load (2)
    - JPEG (IJG-JFIF)       load (1) save (1)
    - MAC (MacPaint)        load (1)
    - PCX                   load (1) save (1)
    - Pictor/PCPaint        load (1)
    - PICT-2 (Mac)          load (1)
    - PNM (PBM,PGM,PPM)     load (3) save (1)
    - PhotoCD (max 768x512) load (1)
    - PNG (PiNG)            load (1) save (1)
    - QRT/POV (Raytracer)   load (1) save (1)
    - SCR (ZX Spectrum)     load (1)
    - SGI                   load (1) save (1)
    - SunRaster (RAS)       load (1) save (1)
    - Targa                 load (1) save (1)
    - TIFF                  load (1) save (1)
    - TIM (PSX)             load (1)
