Consider creating a raw ImageReader (or util class?) that can read raw bitmaps:
    - Interleaved (A)RGB (as in BMP, PICT, IFF PBM etc) -> A1R1G1B1, A2R2G2B2, ..., AnRnGnNn
    - Channeled (A)RGB (as in Photoshop)                -> A1A2...An, R1R2...Rn, G1G2...Gn, B1B2...Bn
    - Planar RGB (as in IFF ILBM)                       -> ....
Formats that internally have these structures could delegate to an instance of this class.
Could also be interesting to allow for raw reading using a RawImageReader.
    - Would need to specify width, height
    - Pixel layout
    - Channel order
    - Compression? RLE/PackBits/LZW/ZIP?
    - IndexColorModel?