rawpy is still supported but will not be bundled by default
due to security concerns
dcraw_emu reads more formats than rawpy + gives better quality
(we told rawpy to use embedded thumbs), so also much slower
dcraw_emu must be combined with libvips or pillow (equivalent)
other alternatives considered:
libvips + a full imagemagick does a different subset of formats,
less than dcraw_emu, yet is 3x slower and eats ram
magick wins wrt formats but is even slower (4x of dcraw_emu)
