I have an image that would change over time. I am using node js to try to detect whether the image has changed in a period of time. I send a request to acquire the image through axios and get the content length for checking. When the content lengths are the same, I assume the image did not change. The problem now I see is that the change in content lengths may not reflect the change in image. May I know if there are other ways to detect the slightest change in image?