This is a JPEG-decompressed spatial corpus. It is NOT comparable to BOSSbase, whose covers were never JPEG compressed. Detector numbers measured here and numbers measured on BOSSbase cannot be placed in the same table. A steganalysis corpus of 10,000 permissively licensed cover photographs and 344,357 matched stego pairs across 35 arms, where every image carries its own licence and every file carries its own checksum. A further 4 arms hold the 38,119 clean halves those pairs are measured against. Nothing is downloaded until you ask for a sample, so looking costs seconds rather than 48 GB. Each arm is its own config, named exactly as the arm table below names it, and covers is the default.…