Adjust image size based on the font size

Question

I am putting together an HTML page to be viewed in both mobile phones and PC/Mac. In the text, I sometimes have inline images:

<p>to do that, then press on button <img src="button.png" /> for 2 seconds</p> 

My fonts are sized in em or % so it is readable on both low res-phones and high-res phones. The issue is that my buttons (usually 32px high images) appear so tiny on high-res phones.

How do I adjust the image size? Preferably pure CSS, but JS is still OK.

Answer 1

If you set the size of your font in the <p> tag, you should just be able to use height: 1em; on p img to set the image's height to that of the font.

Here's a jsfiddle to show what I mean:

body {    font-size: 62.5%;    /*sets 1em to 10px for convenience*/  }    p {    font-size: 3em;  }    p img {    height: 1em;    width: auto;  }

<p>Hello world! <img src="http://images.wikia.com/dragonvale/images/e/e8/Space_invader.jpg"></p>

And if you want it to be double the size of the font, you'd just set the height of the image to 2em.