I would like to add 3-4 images on the homepage and add more later in the future. If you look at the Argos.co.uk homepage you can see they have quite a few images placed in a sort of puzzle look. Is this hard to achieve on the magento homepage? The images will be purely for promo that will link through to certain CMS pages or products. Thanks in advance.
It depends on how you want to manage the items in grid. If you are OK with writing some CSS and using Magento's WYSIWYG editor's capabilities (adding HTML table), this is easy - update Home Page content and done. If, however, you want this grid to be responsive (you should have it responsive, just like your whole site should be), this might require A) more advanced input from you - writing specific HTML that displays images neatly + having custom CSS developed prior to that, B) have custom extension developed to allow only image + link data to be entered (or whatever data you need) - you get nice & easy usability, lose risk of messing the content up... spend more money/time on development.
All in all, task is really easy.