JSFiddle - React, Tailwind, and code Playground

HTML

<table border="0" cellspacing="{$theme['borderwidth']}" cellpadding="{$theme['tablespace']}" class="sideblock">
	<tr>
		<td class="thead">
			<strong><center>Te serwisy polecamy!:</center></strong>
		</td>
	</tr>
	<tr>
		<td class="trow1">
			<center>
				<marquee behavior="scroll" align="center" direction="left" width="880" height="75" speed="0.7" scrollamount="5" scrolldelay="20" onmouseover="this.stop()" onmouseout="this.start()">
					<a href="http://http://et.trackbase.net/"><img class="advert" src="http://et.trackbase.net/img/tb_logo.png" id=foto /></a>
					<a href="https://www.etlegacy.com/"><img class="advert" src="https://www.etlegacy.com/images/logo.png"/></a>
					<a href="https://wolfeket.pl/news.php"><img class="advert" src="https://wolfeket.pl/images/wolfek.png"/></a>
					<a href="http://www.pukawka.pl/pp,piotrekbrt.html"><img class="advert" src="http://etmania.pl/polecane/pukawka_logo_10lat.png"/></a>
					<a href="http://etmods.net/"><img class="advert" src="http://etmods.net/images/etmods_logo_tr.png"/></a>
				</marquee>
			</center>
		</td>
	</tr>
</table>

CSS

.advert{
  opacity:0.5;
  transition:opacity 0.5s;
}
.advert:hover{
  opacity:1;
}
body{
  background:#000;
}