xbi
Personally I think that 97% quality jpeg is good enough, and invisible jpeg noise at this quality level is the least problem compared to brush small mistakes everywhere. I put this this large resolution just because it look better after browser rescale it. When I export to smaller resolutions about 1000px, I use PNG format. JPEG sometimes has issues with smooth gradients, seems not to be an issue here.
I tried to export PNG, it took about 1 minute to export and produce 9 megabyte file, this is too much even for fast internet connections, and derpibooru can't fallback to jpeg preview versions for huge PNGs in fullscreen browser.
Assume I just traded huge picture resolution to jpeg artifacts. This is very usefull and profitable trade. I can put smaller resolution file in PNG file, but this "lossless" format actually lose much more than jpeg for original resolution. It is better to upload original 4000px resolution in good quality JPEGs than downscaled 1000px PNGs with the same file size.
I tried to export PNG, it took about 1 minute to export and produce 9 megabyte file, this is too much even for fast internet connections, and derpibooru can't fallback to jpeg preview versions for huge PNGs in fullscreen browser.
Assume I just traded huge picture resolution to jpeg artifacts. This is very usefull and profitable trade. I can put smaller resolution file in PNG file, but this "lossless" format actually lose much more than jpeg for original resolution. It is better to upload original 4000px resolution in good quality JPEGs than downscaled 1000px PNGs with the same file size.