织梦dede:list标签判断有无图（有图显示 无图不显示）

{dede:list pagesize=20}
	[field:array runphp='yes']
		@me=strpos(@me['litpic'],'defaultpic')?'':"<li><a href='@me[arcurl]' title='@me[fulltitle]' target=\"_blank\"><img src='@me[litpic]' width=\"223\" height=\"154\" /><div class=\"title\">@me[title]</div></a></li>";
	[/field:array]
{/dede:list}

{dede:arclist titlelen='45' row='5' typeid='all'}
[field:array runphp='yes']@me=strpos(@me['litpic'],'defaultpic')?'':"<a href='@me[arcurl]' title='@me[fulltitle]' target=\"_blank\"class=\"preview\"><img src='@me[litpic]' /></a>";[/field:array]
{/dede:arclist}