Check out example codes for "html img size". It will help you in understanding the concepts better.

Code Example 1

<p><img src="image/example.jpg" alt="Example1" width="193" height="130"> (width:193px, height:130px)</p>

<p><img src="image/example.jpg" alt="Example2" width="96" height="65"> (width:96px, height:65px)</p>

<p><img src="image/example.jpg" alt="Example3" width="100%" height="130"> (width:100%, height:130px)</p>

Code Example 2

<img src="img_girl.jpg" alt="Girl in a jacket" style="width:500px;height:600px;">

Learn ReactJs, React Native from akashmittal.com