Reading base64 image from a Buffer is slow

In a browser app I'm reading a base64-string from a buffer. The original image is 3072 x 512 pixels.
This takes quite a while to be read (around 500 ms). Is this normal behaviour?

The image is made of 6 `webp `images of 512x512 each, which I merge with the `merge-images` package, since Jimp doesn't support reading `webp`. The reading of the 6 separate image files, merging them and outputting this to a base64-string with `merge-images` takes only about 250 ms in total.

Here's my code:

```
const base64 = '<... the base64 string of 6 merged webp images...>';
const url = base64.replace(/^data:image\/\w+;base64,/, '');
const buffer = Buffer.from(url, 'base64');

await Jimp.read(buffer)
.then((img) => {

//this takes about 500 ms

}};
```

My system is not slow at all and it has 16GB of memory.

- Browser: Chrome: 125.0.6422.77
- Jimp Version: 0.22.12
- Operating System: Windows 10
- Node version: 20.11.1

Any idea's why reading from a base64 string is this slow?