Flutter: Merge two images and store it in local storage as a single image

Found the answer, Thanks to this awesome library https://pub.dev/packages/image

final image1 = decodeImage(File('imageA.jpg').readAsBytesSync());
final image2 = decodeImage(File('imageB.jpg').readAsBytesSync());
final mergedImage = Image(image1.width + image2.width, max(image1.height, image2.height));
copyInto(mergedImage, image1, blend = false);
copyInto(mergedImage, image2, dstx = image1.width, blend = false);

final documentDirectory = await getApplicationDocumentsDirectory();
final file = new File(join(documentDirectory.path, "merged_image.jpg"));
file.writeAsBytesSync(encodeJpg(mergedImage));