His artistic approach focused on the human element within large-scale conflicts. In works like Combat de Francfort, he used clear compositions to guide the eye through chaotic scenes. Grenier was known for his attention to the specific details of uniforms and weaponry. He often chose moments of active engagement instead of the quiet aftermath of battle. This preference for action made his paintings popular during the July Monarchy and the Second Empire.

Modern collectors appreciate his work for its historical clarity and dramatic composition. These prints provide a window into the military aesthetics of the nineteenth century. The balance between technical accuracy and narrative movement makes his art a strong choice for study or library walls. His pieces offer a sense of scale that complements traditional decor without relying on sentimental themes. They provide a factual look at the Napoleonic era.