Issue with .imdecode(..), .getData(..) and Buffers

Hello,

i would like to get image data loaded by **.imdecode(..)** method and write that data into image file,

so i used this code:

```
let c = cv.imdecode(data); // "data" is a **Buffer** variable
const imageBuffer = c.getData();
const buff = Buffer.from(imageBuffer);
let path = `uploads/${new Date().getTime()}.jpg`;
fs.writeFileSync(path, buff );
```
The code above created the image file, but it is corrupted (it displayed "failed to load image data" in explorer)..

after some researches, i tried this one too:

```
let c = cv.imdecode(data); // data is a **Buffer** variable
const imageBuffer = c.getData();
let ut8 = new Uint8Array(imageBuffer);
for (let i=0; i