How do you delete pictures from your “Flickr” photo stream?

I just have the basic free Flickr account. I can’t see how to delete pictures once I’ve up loaded them.

See here: https://www.flickr.com/cameraroll

Perhaps it’s not possible to delete pictures on my free account because once I get 1000 pictures up loaded into Flickr I will have to start paying to use Flickr.

Thanks.