Saving a photo taking a very long time

I want users to be able to take photos from within my app and have the photos save to their gallery (so that I can later view them in a photo-picker).

I have the following code from react-native-camera, it's basically the bare-bones demo code.

takePicture() {
    const options = { quality: 0.5, fixOrientation: false, width: 1920 };
    if (this.camera) {
      this.camera
        .takePictureAsync(options)
        .then(data => {
             this.saveImage(data.uri);
        })
        .catch(err => {
          console.error("capture picture error", err);
        });
    } else {
      console.error("No camera found!");
    }
  }
}

To move the attachment, I am using react-native-fs, as follows (more basic demo-y code):

const dirHome = Platform.select({
  ios: `${RNFS.DocumentDirectoryPath}/Pictures`,
  android: `${RNFS.ExternalStorageDirectoryPath}/Pictures`
});

const dirPictures = `${dirHome}/MyAppName`;

saveImage = async filePath => {
    try {
      // set new image name and filepath
      const newImageName = `${moment().format("DDMMYY_HHmmSSS")}.jpg`;
      const newFilepath = `${dirPictures}/${newImageName}`;
      // move and save image to new filepath
      const imageMoved = await this.moveAttachment(filePath, newFilepath);
      console.log("image moved: ", imageMoved);
    } catch (error) {
      console.log(error);
    }
  };

  moveAttachment = async (filePath, newFilepath) => {
    return new Promise((resolve, reject) => {
      RNFS.mkdir(dirPictures)
        .then(() => {
          RNFS.moveFile(filePath, newFilepath)
            .then(() => {
              console.log("FILE MOVED", filePath, newFilepath);
              resolve(true);
            })
            .catch(error => {
              console.log("moveFile error", error);
              reject(error);
            });
        })
        .catch(err => {
          console.log("mkdir error", err);
          reject(err);
        });
    });
  };

When taking a photo, this code executes and prints that the image has been moved within a couple of seconds. But, when I look into the built in Gallery App on the device, it often takes several minutes for the image to finally load. I've tried this across many different devices, both emulated and physical... am I doing something wrong? Thanks!