But have you ever tried to get a Lightbox style 'click to zoom' effect in Wordpress.com? Its not immediately obvious, so after figuring it out I wanted to share it.
Firstly, go to your admin dashboard and tick the "Display all your gallery pictures in a cool mosaic" option.
Then, go to a post that has a plain image and start Editing it:
Important: select Multiple Images here and you will get a Continue button:
In the next screen, click Edit and then use the X to remove any superfluous images, so you can just have one image in the 'gallery' if you like:
Set your Layout to Tiled Mosaic and Link to Attachment Page:
After inserting this gallery, you will see that there is a new Gallery object above the old image:
And Update the post:
Now, when you go to the post and click on the image, it will 'zoom' to the image like this:
Here is a live Wordpress.com page with the Carousel 'lightbox' enabled:
Rooms to Polycurves – dynamoworks
And here is a link to some documentation:
Galleries and Slideshows — Support — WordPress.com