I am a real noob at this but i got the images to swap to the ones i wanted
download or if you have the theme in zip form unzip to a folder on your pc.
If you are downloading to edit – goto/ftp /yourwebsite.co.uk/public_html/wp-content/themes/yourthemename/images folder and download the images you want to swap
check properties like image dimensions, rename your new image to the one you are replacing & upload to the images folder overwriting the originals.
