>>305270137
WebP would be the choice to support, as any browser that supports WebM supports WebP. WebP offers losy and lossless compression, along with support for a lossy or lossless alpha channel.
HEIC/HEIF is based on the h.265 video codec, and offers significant improvements in quality for a given file size compared to jpeg. Apple uses it on their devices for pictures. Because it uses h.265 and the related licensing nightmare, support will always be limited.
AVIF seems to be the future of lossy image encoding. Based on the royalty-free AV1 codec, it offers even greater compression at lower file sizes than heic, and compression artifacts themselves are less noticeable than the blocky and noisy compression of jpeg. Supports alpha, lossless encoding more efficient than .png, 8, 10 and 12 bit color. It is completely supported in the most recent version of Chrome and experimentally in the past few versions of Firefox.
JPEG-XL is a very new lossy image codec from the JPEG group, offering about double efficiency over .jpeg and also allows for lossless conversion to and from existing .jpeg images. It may overtake AV1 as the future depending on the licensing agreements because of this lossless conversion. I don't even know any software that supports viewing it right now, though.