1. Having a high density of pixels or dots that compose an image, resulting in excellent image quality. Short for "high resolution." Sometimes styled as "hi-res." I remember how impressed we were when our crappy little flip-screen phones started coming with built-in cameras, but the pictures those things took look positively ancient compared to the high-res pictures modern smartphones are capable of producing. The defendant's legal team successfully argued that only a high-res image could be used to reliably identify place him at the scene of the crime without a shadow of a doubt.

2. slang By extension, satisfactory or good. A: "Was the performance really hi-res?" B: "Nah, I wasn't impressed."