<table>
<tr>
<td><img src="1.jpg" onmouseover="a.this.src" /></td>
<td><img src="2.jpg" onmouseover="a.this.src" /></td>
<td><img src="3.jpg" onmouseover="a.this.src" /></td>
<td><img src="4.jpg" onmouseover="a.this.src" /></td>
</tr>
<tr>
<td><img src="5.jpg" onmouseover="a.this.src" /></td>
<td colspan="2" rowspan="2"><img src="2.jpg" name="a"/></td>
<td><img src="6.jpg" onmouseover="a.this.src" /></td>
</tr>
<tr>
<td><img src="7.jpg" onmouseover="a.this.src" /></td>
<td><img src="8.jpg" onmouseover="a.this.src" /></td>
</tr>
<tr>
<td><img src="9.jpg" onmouseover="a.this.src" /></td>
<td><img src="10.jpg" onmouseover="a.this.src" /></td>
<td><img src="11.jpg" onmouseover="a.this.src" /></td>
<td><img src="12.jpg" onmouseover="a.this.src" /></td>
</tr>
</table>
以上代码可以实现，当鼠标移到一张图片上面时，会在表格的最中间出现，图片的大小自己调试。
