Have a seat. Let's take a minute to talk about Image Resolution.
If you send us an image file, like a .jpg or .psd file, that image was created with a fixed quality resolution that is measured in pixels (or dots) per inch. This determines not only the visual quality on-screen, but also print quality.
Ideally you want your Image Resolution to be 300 dpi or more at actual size for the image to look crisp and clean. Anything below that may appear blurry, blocky, fuzzy, or low-quality when printed as you can see in the example comparison above. 
For Best Results: build your original artwork or capture your image at 300 dpi. Or opt for creating your art out of vector graphics in Adobe Illustrator to stay extra crispy at all times.
Any questions?