Does Somebody Know How To Re-compress Images With "OptiPNG" , Is It A Great Re-Compression Tool?

Question

I have tried to use "OptiPNG" to recompress images , but the result isn't very well ,and I was following opertaion document to do it , like optipng - o7 ***.png , it just decrease under 5% , so what's wrong with me or tool. Thank you for your patience if you have read my question to the end.

PS :

How to Maximize PNG Image Compression With OptiPNG as following URL, depending on content it show very high decrease radio , but in my case it isn't good for me with my image, why ????

http://sweetme.at/2013/09/11/how-to-maximize-png-image-compression-with-optipng/

Answer 1

Gains reported in the article are abnormally large, not what you usually expect by using different PNG compressor implementations.

Without your or their images for testing, it's difficult to say, but my guess is that

• you're using the tool correctly, your results seem reasonable
• the gains reported in the article are for very small files (100x100, as I can read), so most of the gain is due to removing metadata via the -strip parameter.

That said, JPEG-LS is typically better for lossless compression, and JPEG2000 is also worth a try.