What is the term for adjusting the number of pixels in an image?

The term for adjusting the number of pixels in an image is "resample." Resampling in Photoshop involves changing the pixel dimensions of an image, which can be done by either increasing or decreasing the number of pixels. This process affects the image's quality and size; for example, increasing the pixel count can lead to a larger file size but may also result in a loss of sharpness if not done correctly because it requires interpolation, which estimates pixel values.

By using the resampling option in Photoshop, users can choose to either maintain the original aspect ratio or alter it, thereby controlling how the image is displayed or prepared for printing. This adjustment is essential for ensuring that images retain the necessary detail and resolution appropriate for their final output, such as web usage or high-quality prints.