thank you for purchasing our theme. The solution is very simple: go to WordPress admin and then edit the item you want to change the images. Then click “add media” button below the editor. In the popup there is a dropdown, click “uploaded to this page”. Now you will see only the images for this page / post / portfolio / property. Click the image you want to delete. At the side of the popup appears some information from this image, and also a link “delete permanently”, here you can delete the images.