http://chen.imgix.net/rose.png?w=560
What other upsamplers look like: https://github.com/haasn/mpvhq-upscalers/blob/master/Rose.md
Looking at the other operations available, I fail to see what is done better by Quartz than just by imagemagick.
The downsampling also isn't that great.
Original image: https://raw.githubusercontent.com/haasn/cms/master/rings_lg_...
Downsampled with imgix: http://chen.imgix.net/rings_lg_orig.png?w=400
Downsampled with imagemagick: https://0x0.st/1-.png http://i.imgur.com/Nvl7tAm.png
Downsampled with imagemagick, gamma correct: https://0x0.st/1i.png http://i.imgur.com/Hrm4COb.png
Note how the luminance becomes square in the center (step back a bit if you can't see it), and also the edge pixels on the imgix version.
You don't even have to click the link, just simply get Chrome to load it into memory
edit: looks like something to do with Chrome's pre-fetching and https cert parsing, I think they're literally parsing the "0x0" string within the cert as a memory location
Most importantly, it doesn't have the horrible box window that the imgix resampler has.
Then again, one wonders why not just use FreeImage or something?
I imagine, especially if the traffic is mainly for downsampling, it'd be sufficient. If it's not, then writing some custom code to do the image transforms on a GPU and bring them back shouldn't be that gnarly--and if you can afford to stick a shitton of macs in a data center, you can afford a graphics programmer to get that done.
Isn't running shaders intensive as it needs to be compiled on the fly and handed off to the GPU driver?