I was able to extract a higher-resolution version of the image from the "Sousai Shojo Teien" web page.

The hagoita/paddle that Ritsuka is holding has a representation of Madoka's dog (or at least the same breed of dog); it looks like it would be more for decorative purposes than for actually playing hanetsuki with it.

They could make some really nice fixed-pose figures of the girls based on this illustration; the outfits are really pretty!