In PHP there is no way because the language does not work with this, but HTML is wrong and wrong in your code. PHP is just an agent that is generating HTML for you, so the question has nothing to do with this language, unless it is quite different from what is described.
The tag <a href>
is the one that determines that there will be a link there. It exists by itself, what it will have inside may be various HTML elements, it may be a text or it may be an image. HTML tags are tags within each other.
<a href = 'seu URL aqui'><img src = 'empat1.png'/></a>
If you want more readable:
<a href = 'seu URL aqui'>
<img src = 'empat1.png'/>
</a>
In the case of others it is only necessary to reproduce this code with the image name that is displayed and the link :
if ($formaCombate == "patk") {
if($patk1 > $patk2) echo "<a href = 'jogador1ganhou.html'><img src = 'venceu1.png'/></a>";
elseif ($patk1 < $patk2) echo "<a href = 'jogador2ganhou.html'><img src = 'venceu2.png'/></a>";
else echo "<a href = 'empatou.html'><img src = 'empat1.png'/></a>";
}
Documentation: