Hello stevemib -
unfortunately, if you are trying to upload your images to your Auctiva account, you will not be able to do so via .csv file. The image uploader within an Auctiva account is the only way to get your images to be stored in your account.
If you are using an external source and just need to include the URLs for the images, you can do this using the .csv file and using the pipe character ( | ) in the PicURL column to separate the URLs in the you can upload multiple URLs for your images in the .csv file.
If you run into difficulty with your .csv upload, please feel free to file a support case from under the Help tab letting us know what you've run into and we'll be happy to look into it.