Hello there!
I've done repack of your png-graphics for your mod! So now mod files are ~70% smaller in size (so all your graphics size now is1 Megabyte) without visible changes! I'm sure you rate it high ;)
https://ufile.io/9hyjc
Best regards!!!

Very nice, went through and did a comparison with the originals to make sure. I'll replace them with yours in a bit and push an update in the next few hours.

Good stuff!

Was it done with this PNG optimization script? https://forums.factorio.com/viewtopic.php?f=70&t=30591#p224304

This is done with last version of Pinga app, that already can reduce unused palette colours (in PNG optimization script that reduce was made by additional pre-run of pngquant app). There is some minor posibility to reduce filesize of png's some more, but this can be done only with reducing overall number of colours in images that can (and mostly WILL) corrupt visual quality.

P.S. I'm sure that every modder that use .PNG in their mods must optimize their files with PINGA app. This can reduce filesize (up to 90% in some cases). Settings that almost never corrupt quality in our Factorio case are: [Compression = "lossy (strong)"], [Compresion level = "max"], [Quality = right "+" (set to the right position)] , [off dithering]. In many tests this settings provide imo best compression rate without any visible difference ingame. Thanks for listening.

Did the modder take the files? Because they aren't there anymore. And I just noticed that this mod is over five megabytes!! o.O Why so huge?

Ran the files thru TinyPNG. Reduced total size by 4MB
https://i.imgur.com/YpsPtMZ.png

BTW the menu graphic for the underground belt needs updating. It's still using the 0.16 style.

I was waiting for text plates to be updated before redoing the thumbnail, but I went ahead and updated textplates myself locally, so with the optimizations and updated thumbnails, I've pushed an update.

And I did remove 0.17.1, only like 2-3 people had it and it had only been out a few minutes. In hindsight perhaps I should have left it, unless that's not what you're referring to?

No I was referring to the link given by drd_avel above, which was supposedly a smaller version of your PNG files. The link is now dead, so I unzipped the mod and removed 4MB from the total size by sending the files to TinyPNG. If you do the same, you'll have a far smaller mod.

It's been done. :)

Indeed. Excellent!

About the link from drd_avel, it was graphics for 0.16. Had to redo them for 0.17 since all the belt-related graphics changed, haha.

Optimized to 1.07Mb with Pinga only.
https://ufile.io/1qwn2
P.S.> Inspected and analyzed compression that provided by tinypng: that script working so that you get smaller and smaller png-file ANYWAY!!! This is impossible without a permanent and continious decrease of image quality, what that script does. Because without deterioration in quality, it is no longer possible to reduce the size of this graphic. Therefore (imho) tinypng playing a dishonest and dirty game with png.

What settings did you use with Pinga to get 1.07Mb? I can only get it down to 1.52Mb with Pinga using your recommended settings above.

Okay. I use reduced palette number (first positions of "Quality" settings provide 96, 128, 160 and so on colours in result palette) and "Grayscale" checkbox (in shadows and masks images), but only when result is absolutely visually same as original. In compexed images with many colours and gradients we must use Quality to last "+" position, or else we can get visual decrease of image quality.
Best regards. Also you can read https://css-ig.net/articles/lossy-png-optimization and other articles from there to get the point.