There's a huge number of woefully unoptimized PNG images in circulation.

For those unaware, PNG is a lossless image format. However it supports many, many methods of image encoding and compression, all of which (barring software bugs) will result in the *exact same* bitmap data.

There are many tools for png optimization, but for this example I'm going to be using what I have and am familiar with, pngcrush - there are other tools available, mostly non open-source, that theoretically can get a fraction of a percent even more compression than pngcrush.

Taking post #2722713 as an example:

pngcrush -brute -ow 835463e08fe57a6139e252a23f4a23fd.png

Yields a file that is 10,114,461 bytes, verses the original 11,909,012 bytes.

I think it would benefit everyone concerned, including the esix infrastructure and everyone who downloads the image, to replace the original with this optimized version.

If I was to do this on any kind of large scale, I'd be flagging a _lot_ of posts for removal, and I'm wondering if there are any "etiquette" concerns for doing this?

Using whatever version is provided by the artist or commissioner is probably best. Most people aren't going out of their way to optimize PNGs, and even if we were to accept optimized PNGs as a rule, that seems like it'd encourage a really weird arms-race between uploaders trying to post minutely more optimized versions.

lafcadio said:
encourage a really weird arms-race between uploaders trying to post minutely more optimized versions.

If I was to start doing this, I'd set a target for myself. If the optimization doesn't shave at least x% off the filesize, I leave the original alone. I'd probably target a minimum 4% reduction?

Do not take images from here and repost them, we will delete them. Don't mess with images from artists unless you need to in order for them to be postable.

millcore said:
Do not take images from here and repost them, we will delete them. Don't mess with images from artists unless you need to in order for them to be postable.

And this is why I ask before doing things. Thanks!

For private use I use FileOptimizer, which runs files through multiple bundled filesize optimization programs. It's got its drawbacks (like a lack of multithreading), but it does the job it sets out to do.

I don't know if Pngcrush is faster or better than FileOptimizer but the fact that it was bundled but removed after 2 days says something to me.