Centre entry-content

I've added a selection of images to a page http://ranirai.com/home/sculpture/ and I would like to centre this block of images on the page. Centre justifying each image seems to create a vertical line of images, putting the cursor in the centre and importing them in one go messes up the spacing between them and makes editing in future more difficult. I have tried adding .entry-content {text-align: centre;} in Additional CSS but this doesn't seem work. Any thoughts on what I'm doing wrong? Thanks, Ralph