TipsTricksTests.java

public void takeScreenshotOfElement(WebElement element, String fileName) throws Exception {
    File screenshotFile = ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE);
    BufferedImage fullImg = ImageIO.read(screenshotFile);
    Point point = element.getLocation();
    int elementWidth = element.getSize().getWidth();
    int elementHeight = element.getSize().getHeight();

    BufferedImage eleScreenshot = fullImg.getSubimage(point.getX(), point.getY(), elementWidth, elementHeight);
    ImageIO.write(eleScreenshot, "png", screenshotFile);

    String tempDir = getProperty("java.io.tmpdir");
    File destFile = new File(Paths.get(tempDir, fileName + ".png").toString());
    FileUtils.getFileUtils().copyFile(screenshotFile, destFile);
}