set height and width to 100% as mentioned below :
<img src="../Advertise/Add1.jpg" style="height:100%;width:100%" />
HTML:
<table>
<tr>
<td></td>
<td style="table-layout: fixed; border-collapse: collapse;">
<marquee direction="down">
<table>
<tr>
<td>
<img src="../Advertise/Add1.jpg" style="height: 100%;width: 100%" />
</td>
</tr>
<tr>
<td>
<img src="../Advertise/Add2.jpg" style="height: 100%;width: 100%" />
</td>
</tr>
<tr>
<td>
<img src="../Advertise/Add3.jpg" style="height: 100%;width: 100%" />
</td>
</tr>
</table>
</marquee>
</td>
</tr>
</table>