First of all, the animals in the paintings, yes, some of them were hunted by the cave painters, but many of the animals painted were probably not hunted, for example rhinoceroses and cats. And while archaeological evidence indicates that reindeer were the most hunted animals. Reindeer aren’t painted at all. Moreover, only a small percentage of the animals are shown wounded by spears or arrows. So they cannot support the view that the cave paintings were specifically associated with hunting.
Second, the human figures in the paintings, some travel-hunters may have used animal hides while hunting. But the human figures with the animal hides in the cave paintings are not shown hunting, they are not even standing up. Instead the figures are shown in a horizontal position on their backs like they were asleep. And the figures are not presented with other images that might help us interpret them. So we just don't know what these pictures are about.
Third, the fact that images are often considered to a magical property doesn't necessarily mean the purpose of the magic was to ensure successful hunting. The Lascaux cave images may have had a different type of magical use. For example, many cultures believed that the spirits of their ancestors live on in some animals around them. People in such cultures believe they can communicate with ancestors’ spirits through ceremonies in which images of the animals play an important role. The Lascauxcave paintings may have played a role in these kinds of magical ceremonies.