Flag Girls.  It is a series of 12 images, but there are 6 different types.  Here's the checklist.
1. Belgium
2. China
3. England
4. France
5. Italy
6. Persia
7. Portugal
8. Prussia
9. Russia
10. Spain
11. Turkey
12. United States

 
Type 1 - No country or brand listed on front - backs are blank.
Type 2 - Country listed on front, but brand is not listed - backs are blank.
Type 3 - Country and Leidersdorf Red Clover brand listed on front - backs are blank.
Type 4 - Country and Leidersdorf Uncle Sam brand listed on front - backs list the Uncle Sam brand and an offer.
Type 5 - Country and Gold Star brand listed on front - backs list the Gold Star brand, Gradle & Strotz, and an offer.
Type 6 - Country listed on front, but brand is not listed - backs list Railway Long Cut

This would make a master set = 72 cards.  Between the chat thread, Todd's site, and the internet, we have 24 images (one-third of a master set).
 
The cards are not numbered.  The numbers used are based on alpha sequence.