Digital Art Pixelation Removal

I'm seeking a professional to help clean up my digital art. The artwork is currently pixelated and needs to be smoothed out for a high-quality JPEG output. These images were sent to me is smaller format but need to be blown up to be used as wall murals. I have 11 of these that need to be done asap.

Key Requirements:
- Expertise in image editing, specifically with digital art
- Ability to produce a high-quality, detailed final image
- Proficient in delivering the final product in JPEG format

Ideal Skills:
- Advanced knowledge of Photoshop or similar image editing software
- Strong attention to detail
- Previous experience with digital art enhancement