Faire de l'image à l'intérieur de div prenez toujours la même quantité d'espace

<div id=“parent”>
    <div id = "child1">
       <img src="123"/> 
   </div>
   <div id = "child2"> 
      <p> Some text1 </p>
      <p> Some text2 </p>
   </div>
</div>
I have parent div with fixed height. Parent div always have 2 child containers: 
1 clild - div with image 
2 child - div with some data
The image inside the container can be different in size. Sometimes, when image is larger, it takes more space inside #child1 and my #child2 with text becoming only half-visible. I can see the "Some text1 " paragraph, but not "Some text2".How can I make my image inside #child1 take always same % of space inside #parent? (Probably, by zooming it in)