<div style="font-size:0;">

    <img data-src="http://image.zhangxinxu.com/image/study/s/s128/mm1.jpg" />

    <img data-src="http://image.zhangxinxu.com/image/study/s/s128/mm2.jpg" />

</div>
font-size：0；表示两个图片无空隙。但是FF不兼容

<div style="letter-spacing:-4px;">

    <img src="http://image.zhangxinxu.com/image/study/s/s128/mm1.jpg" />

    <img src="http://image.zhangxinxu.com/image/study/s/s128/mm2.jpg" />

</div>
letter-spacing:-4px;更加靠谱