PNG compression - room to improve?

[rotbus19]

Sample file attached, size = 248KB. Compression with different tools, using the same settings as much as possible (e.g. 256 colors):

• https://squoosh.app/ / https://github.com/GoogleChromeLabs/squoosh = 97KB
• https://github.com/Lymphatus/caesium-image-compressor = 113KB
• https://github.com/JacobDev1/xl-converter = 123KB
• XnView MP = 168KB

So, XnView is 73% bigger than the smallest. All the other tools use https://github.com/shssoichiro/oxipng.

Could XnView use Oxipng to improve its compression?

[XnTriq]

There's a color profile embedded in displaycomparisonfull.png.
Unlike some other programs (like PngOptimizer), XnView retains profiles.
IMO it's a bad idea to delete them without asking the user.

[rotbus19]

Thanks, I didn't check them all for stripping meta data but I just ran the latest Oxipng with '.\oxipng -o 4 displaycomparisonfull.png', and it reduced the test image to 93KB while retaining meta data / color profile.

So, even worse for XnView - 168KB versus 93KB, like for like.

P.S. Stripping the metadata only shaved off 2KB from the 93KB output.