As we need to define an image with amp-img tag for an amp page, the problem is with the responsive nature of those image. For example:
<p align="center"><amp-img width="400px" height="200px" layout="responsive" src="https://xyx.com/abc.png"></p>
Now if the master div is 600px then, the image will get stretched out to 600px (more than its normal 100%), but for a mobile device with master div being 300px , the image will adjust the height and will be perfectly fine as it will get contained in the 300px div stretching it to 100% won't make effect. Also, layout cannot be set to fixed because it will then stretch out of the mobile display. What's the solution?
If you have dynamic width of the image and want to handle this situation than go to this link : https://ampbyexample.com/advanced/how_to_support_images_with_unknown_dimensions/ and read "Fixed-Height Layout with correct Aspect Ratios" section. It will help you to implement amp-img when you do not know the image width and do not want the image to be get stretched.