Copyright law has a lot of complexities, and it varies a lot from country to country. If the images are going to be publicly available on the web, for your own protection you should either (a) not use them, (b) get permission from the copyright owner to use them, or (c) consult with a copyright lawyer to determine if you are liable for using them as you intend.
As far as the layout goes, I would suggest using a separate style sheet rather than bloating your HTML with lots of style= attributes that have to be downloaded with every page load, whereas a stylesheet will be cached.
You might want to wrap the contents of each TD within a DIV. You can then style those DIVs to be a fixed height and width, and use the overflow:hidden style for those DIVs.
<table id="map">
<tr>
<td>
<div>
<img src='some_image.png' alt=''>
</div>
</td>
</tr>
</table>
Stylesheet:
#map div {
height: 70px;
width: 70px;
margin: 0;
padding: 0;
text-align: center;
overflow: hidden;
}
(Adjust height, width, margin, padding as desired.)