Which characteristic of a radiographic image indicates the ability to image small objects with high contrast?

The ability to image small objects with high contrast is primarily linked to spatial resolution. Spatial resolution refers to the smallest detail that can be seen in an image, reflecting the imaging system's capability to distinguish between closely spaced structures. A high spatial resolution means that fine details and small objects can be discerned clearly, which directly correlates with the sharpness and clarity of the image.

In imaging, while other characteristics such as contrast resolution also play a role, they focus on the system's ability to differentiate between varying levels of intensity and shades in the image rather than the clarity of small details. Therefore, spatial resolution is the key characteristic indicating the capacity to visualize small objects distinctly. The fact that spatial resolution is prioritized for detail visibility makes it the correct answer in this context.