How to filter Dynamic List Content?

Hello everyone!

I need a little help:

I have this Dynamic List Content:


<content target="pictures" sortby="random" limit="7">$INFO[Container(997).ListItem.FolderPath]</content>


But, this show all itens in the folder, and I want only to show especific files, like .jpg and the rest of types keep hidden. 

It's possible to apply some filter in the syntax?

Thanks in advanced!