The clip you are showing is a "Dress Clip." They were used from the late 1920s into the 1950s - often in pairs, sometimes to change the necklines of dresses or gowns and sometimes just for decoration. If you would like to learn more about them, there is some discussion of dress clips in Part III of this Jewelry Workshop: https://forums.vintagefashionguild.org/threads/vintage-jewelry-workshop-part-iii.35686/
We should probably start a new thread for this question but very simply, shoe clips have very "pointy" prongs and are much smaller. Here are two examples of shoe clips:
