http://maximumcompression.com/data/files/jpg-test.zip
Code:
842,468 A10.jpg // original
780,872 A10p.jpg // jpegtran -optimize -progressive -copy none -outfile A10p.jpg A10.jpg
688,273 A10.lep // lepton20160715.exe A10.jpg
686,974 A10p.lep // lepton20160715.exe -unjailed -allowprogressive -multithread -skipvalidation A10p.jpg
673,197 A10.pjg // packJPG.exe A10.jpg
673,150 A10p.pjg // packJPG.exe A10p.jpg
630,296 A10.jpg.paq8px // paq8px_v100.exe -7 A10.jpg
772,785 A10p.jpg.paq8px // paq8px_v100.exe -7 A10p.jpg
Yes, but "result_corpus.zip" includes compression rates.
I think its very important to take as a reference not just a normal jpeg, but recompressed jpeg.
Also I kinda doubt that pik is better than paq8px.