RQSHC is an experimental Windows image compressor with its own RQI format.The core compression and decoding paths are original native C++17 implementations with selected x64 assembly and AVX2 optimizations, rather than wrappers around an existing image codec library.The current release supports PNG, BMP, and PPM input, and includes a separate Windows viewer for RQI files. Processing is performed locally on the user s PC.The compression core is currently closed source, but the binaries are free for personal use, research, education, company evaluation, PoCs, and public benchmarking.