Camera Preview - Image quality/size

Hi, I am using ionic 3 camera preview plugin. I tried to pass different options to CameraPreviewOptions but there is a reduction of size and quality after taking a picture. When I try to upload, the image get uploaded with size less than 1mb while it should actually be 5mb+ (a usual photo size taken by my phone).

Here is my client code:

  openCamera(){
     const cameraPreviewOpts: CameraPreviewOptions = {
        x: 0,
        y: 0,
        width: window.screen.width,
        height: window.screen.height,
        camera: 'rear',
        tapPhoto: true,
        previewDrag: true,
        toBack: true,
        tapToFocus: true,
        alpha: 1
      };

 // start camera
 this.cameraPreview.startCamera(cameraPreviewOpts).(res) => {
    this.isCameraReady = true;
  });
}

 takePicture(){
    const pictureOpts: CameraPreviewPictureOptions = { 
        quality: 100,
    };

   this.cameraPreview.takePicture(pictureOpts).then((ImageData)=>{
       let pic = 'data:image/jpeg;base64,' + ImageData;
       this.upload(pic);
   });
 }

Setting the width and height inside pictureOpts didn’t help either.