Selenium AShot: Why Screen shot of an particular element is white

Question

On this webpage: https://www.selenium.dev/downloads/ I am trying to capture the screenshot of an element that is an img tag. You can inspect : img[alt='Java']

This is the img element I want to capture: Element to capture

So to capture the above element I wrote this code:

WebElement imgJava = driver.findElement(By.cssSelector("img[alt='Java']"));
Screenshot screenshotJava = new AShot().shootingStrategy(ShootingStrategies.viewportPasting(100)).takeScreenshot(driver, imgJava);
ImageIO.write(screenshotJava.getImage(), "png",new File(System.getProperty("user.dir") + "\\javaImg.png")); 

But when I opened the image, it is just all white: Image after caputring

And if I remove the shooting shotingStrategy and just use new AShot().takeScreenshot(driver,imgJava); It will take screenshot of whole page even though I passed a particular element: Whole page