I've made this a while ago and updated it this week. It's a site to showcase various image codecs and still image from video codecs. You can compare codecs at various quality on a subset of 50 pictures from Xiph. Some typical metrics are also presented (VMAF, PSNR-HVS-M, Y-SSIM, RGB-SSIM, MS-SSIM).
My hope is that one of the next-gen video codec will be picked up as a new format to replace the venerable JPEG.