max-width: Maximale Breite

<div style="width:200px;max-width:300px;border:1px solid #0000ff;">
max-width:300px&nbsp;max-width:300px&nbsp;max-width:300px&nbsp;max-width:300px 
</div>

max-width:300px max-width:300px max-width:300px max-width:300px

<p>
<img style="max-width:10%;"src="../images/logo_expl.png" alt="CSS 4 You" />
<img style="max-width:20%;"src="../images/logo_expl.png" alt="CSS 4 You" />
<img style="max-width:30%;"src="../images/logo_expl.png" alt="CSS 4 You" />
</p>

10%: CSS 4 You 20%: 30%:

<p>
<img style="max-width:50px;"src="../images/logo_expl.png" alt="CSS 4 You" />
</p>

50px: CSS 4 You