How can flickr recognize that a cropped picture came from a specific camera?

I photographed a painting of mine and cropped it in Paint ShopPro. Saved it as a Jpeg and put it on Flickr.
http://www.flickr.com/photos/puppyzwolle/2233424074/

How can Flickr recognize it came from a camera when I did that to it? Where did that info come from?

2008-01-31T13:53:17Z

This is the first Photograph I have added using this camera and I did not input that information. Obviously. Else I would know the answer to this question >;-)

2008-01-31T17:45:16Z

I get how this is stuck to the original photo... but...
I Copied a portion and pasted as a new image.
How does the info keep with this new detail?

Anonymous2008-01-31T16:10:38Z

Favorite Answer

EXIF data!
What is EXIF data?
Thanks to new technology almost all new digital cameras save JPEG (jpg) files with EXIF (Exchangeable Image File) data. Camera settings and scene information are recorded by the camera into the image file. Examples of stored information are shutter speed, date and time, focal length, exposure compensation, metering pattern and if a flash was used. If don’t want that information to show, from your flickr setting you can turn that option off.

PS:

Nice picture!

Anonymous2008-01-31T14:21:56Z

Because the camera is adding "exif" information to the JPG's. Which generally will say what kind of camera it is, shutter speed, aperture, iso and other miscellaneous data.