Hello @BobB50 ,
Unique images wouldn't really be possible, the best option would be to have a custom field for whatever this amount is , and re-import / update contacts that have the applicable field info. That way you can utilize the insert contact details functionality, and have that contact's specific number show when it's sent to them.
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At this time, we do not have plans to have a feature to replace contacts an existing list. You can upload the contacts as a new list and delete the previous one.
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