Hi,
You can go to the menu System->Shipping methods. There, select the manual shipping methods plugin. On that page, you will be able to create new shipping methods and configure them. You will be able to change their names and images. If you need to add more images to the pool of shipping methods images, you can upload them to the folder components/com_hikashop/images/shipping via FTP. You will then be able to select them on the images selection interface with editing your shipping methods.
Also, please make sure that you are using the one of the latest version of HikaShop as HikaShop now accepts all format of images where before it was limited to png.
