There are more usage of image lists in RealityCapure. You can use it to import images or to select images, which have already been imported.
Image list can be exported in the Alignment tab in the section Export. In the case there are no images selected in the 1Ds view, exported image list is going to include all images. If you want to export only certain images, you will have to select them first. Image list is going to be made only from the selected images.
Once your image list is exported you can use it to import images found in that file into RealityCapture. Use Inputs button found in the alignment tab to find image list file and import your images, or jut drag and drop your list into RealityCapture.
In order to select the images in an existing project, import the image list file via Image Selection button found in the Import&Metadata section of the Workflow tab.