The rayimage package is distributed under GPL-3. The package also bundles third-party header-only code in inst/include and src/ext: - inst/include/tinydng/tiny_dng_loader.h and inst/include/tinydng/tiny_dng_writer.h Copyright (c) Syoyo Fujita and contributors. These files are distributed under the MIT license terms included in their headers. - inst/include/stb_image_resize.h and src/ext/stb_image.h Sean Barrett stb code. These files are distributed under the public domain terms included in their headers.