T-Shirt Design High-Res Conversion

I have downloaded some T-shirt designs from Google which I need to print on T-shirts. These designs need to be converted to high-resolution PNG files that I can use for printing.

Requirements:
- Convert existing T-shirt designs to high-resolution PNGs
- Maintain the integrity of detailed illustrations
- No need for design modifications, just a high-res conversion

Ideal Skills:
- Graphic Design
- Print Design
- PNG Formatting

Please note, as I'm working with detailed illustrations, your attention to detail will be key to ensuring the designs are print-ready.