Little windows

Postcards are amazing little things.  They are social commentary, giving us a peek into what people thought in a by-gone time, and also little bits of retail:  who bought what and to send to whom?   My good friend Rose got me interested in postcards and, mostly because of her generosity, I have a lovely little collection of Krampus and rat cards, mostly vintage.  

A particular card caught my eye recently, this one:  

It features a lot of white mice having a good time, more or less realistic with a bit of whimsy. 

Attempting to find out more about this card online, I found this painting:

and was immediately struck by the similarities.  The overall placement of objects is very similar, but elements like the tipped glass on the right, the spoon in the jam, the partially eaten brioche on the left, etc... are copies of each other.  And if you look closely, some of the mice are identical! 

Take a look at these two images: 

While the postcard has a lot more mice, these two in the painting are obviously the same as in the postcard image.  

So the question is:  which came first, the postcard or the painting?  The postcard is dated 1904 by C. Riviere (perhaps Charles Riviere) while the painter, A. Bechard, is from the 19th-20th century but that's all I know so far.  This painting is for sale on the Proantic website and I have attempted to contact the vendor but have received no reply.  

If anyone has any insight or ideas, please contact me!