To replace the default homepage banner image with your own image:

• In your CoreCommerce admin, go to Design > Manage Store Images

• You'll want to look for the banner image. It's typically called "banner.png." If the image is not labeled, "banner," simply match the banner image in the default store with the image preview to the right.
• Once you find this image, click the Edit link over to the right and you can then upload your own image to replace it. Your image must also be in .png format.
• Make sure to Save.