However, when I do so upon saving the changes it automatically gets changed to the below HTML code and the details about the National flag gets disappeared:
Because what you entered is not a valid HTML code to show the image. So, the system automatically removes additional codes that contain empty values. Indeed, you forgot to put the source URL of the flag image in that code.
You should simply enter a code like this:
You can replace the value inside src with any image address you want.
You can not use a local image since you want to show it on the web. So you should first upload it on any (free or paid) web hosting (like postimages.org) and then replace its URL with the one I entered in the above code. Even it is better if you upload it here on Connect and copy its link and paste it as src.
Thanks @Amiran . It worked. Earlier I was using different url for Local Connect which gets displayed on the browser in the address bar. Now, I have used the url which I got it through right click the designated picture and copied the url.