cropping and losing pixels?

[liverlipsyyz]

hi. when i crop in photoshop cs3 i usually create new document smaller than the original and then i add guidelines in thirds (for rule of thirds stuff). i drag the photo on to the new document, position it how i want, and then crop the whole thing on the outside of the frame. when i save it i notice the file size is a lot smaller then the orignal. sometimes the original is 2 million or so and when i save the cropped version it's usually less then 1 million or sometimes 500,000. does this mean i'm losing quality? i'm not sure if i explaine that properly or not.

[Japaslavian]

If I'm understanding you correctly, you're not losing quality, you're losing resolution.
The image has become physically smaller, thus your file size decreases.