Final answer:
The result of setting an image's opacity to 0 percent in Photoshop is that the image becomes completely transparent, rendering it fully see-through with no visible content from the image itself.
Step-by-step explanation:
When the opacity of an image in Photoshop is set to 0 percent, the result is that the image is completely transparent. This means that the image is fully see-through and anything behind that layer in the composition will be visible instead. In terms of levels of visibility, transparency denotes the absence of any visible content from the image, whereas opacity refers to the image being visible. As you adjust the opacity level closer to 100 percent, the image becomes less transparent and more opaque until it is fully solid at 100 percent opacity. Therefore, an image with an opacity of 0 percent will not show at all in your project.