Yes, that would work, The only other way to do this would be a nested if on empty image, for example:
<?php if($row_Recordset1['newsPhoto'] = "") { ?>
<?php if($row_Recordset1['newscat'] =1) { ?>
<img src="imageA.jpg" />
<?php } else if($row_Recordset1['newscat'] =2) { ?>
<img src="imageB.jpg" />
<?php } ?>
<?php } ?>