That's pretty good if you ask me! I was using an image encoder that had a WebAssembly SIMD CMake option, which is nice, but it only had half of native performance. I suppose it will continue to improve over time.
Depending on the browser and also when this was WASM SIMD could have been a pessimization. It added first with compatibility in mind and took/is taking awhile to reach full performance potential
This is not a typical app.
Encoding images is a pretty typical thing to do though?