Add a new instagram widget

Follow the instructions here.

Images Are Not Like the Demo

When you upload images to your posts, always select "Original size". It doesn't matter if the images you upload are bigger than the post area - the CSS in the template will resize them to fit. If they are smaller than the post area, they will remain their original size to keep them from appearing blurry.

Make sure at least the first image in each post is bigger, especially if there is a slider/custom featured posts widget. 1100px wide or bigger should look good.