Changing the Resolution
Images from scanners, cameras, off the 'net etc. all have varying dpi. Digital cameras can capture at 72, 120, 150, 180 or 220 dpi. Scanners can be set to capture at just about any resolution. Negative Scanners capture at higher resolutions still, from 1500 dpi to 2500 dpi. Drum scanners take it even higher.
Ultimately if you need to publish your images to the web, you need to change the resolution to 72 d pi. This process is known as "re-sampling". When you change an image's d pi, Photoshop, by default, will also change its physical size. The easiest way to fix this is to change the resolution first then adjust width/ height settings to suit.
Learning Activity 2:
Re-sampling images aka "re-sampling"
|LIKE A LIONESS|
Resample the lion to 72 dpi with 960px width.
Re-sample potter to 72 D PI with 400px width.
|Resample loch.jpg to 72 dpi with 960 width.|