Image Resizing & Resampling

Physical Size (W x H in inches) = Resolution (PPI) x Pixel Dimensions (Xpx * Ypx)

Pixel Dims control image data, and therefore directly relates to image file size (MB/GB).

Physical size & Resolution determine print quality.

Resizing without Resampling keeps Pixel Dims constant.

Change Physical Size & Resolution simultaneously.
Larger phys size reduces resolution, and smaller phys size increases resolution.

Resizing with Resampling changes Pixel Dims (and therefore affects file size).

Resampling is changing pixel count (X x Y) and affects / degrades image quality.

Upsampling (adding pixels) is worse than downsampling (removing pixels).

Resizing with resampling allows independently changing Phys Size, Resolution (and Pxl Dims).

With inputs from:

ASTROFOTOPHUNDA