For your collection of images in the CSV file, please use this specific format (it is assumed this text string is enclosed in quotes - as shown - as it exists in the CSV file):
"catalogue124/02.jpg,catalogue124/04.jpg,catalogue124/05.jpg"
CubeCart will insist that images (with sub-folder path) mentioned in this string must eventually exist in /images/source/. Thus, only that distinctive part of the path/name can be allowed.
Until Github issue #2923 is solved, do not have spaces following the commas, and do not use leading periods.