Ok I give up. EXIF data? What are you talking about?

JP
Here you go John.....
Exchangeable image file format (Exif) is used to record your cameras settings when taking a photograph. This data stays with the original photo and is viewable (by using suitable software) even after editing unless the image is saved in a way that the exif data is stripped, i.e. saving for the web in Photoshop. I've pasted some of the exif data from a recent edited photograph of mine below.
Here's a link for more info and an exif viewer
CLICKYPhotoshop PSD Header
Mode : RGB
ImageWidth : 2389
ImageHeight : 3539
Main Information
Make : Canon
Model : Canon EOS 30D
Software : Adobe Photoshop CS3 Windows
DateTime : 2008:10:07 09:25:50
Sub Information
ExposureTime : 1/4000Sec
FNumber : F14.0
ExposureProgram : Manual
ISOSpeedRatings : 100
DateTimeOriginal : 2008:10:05 18:26:00
ShutterSpeedValue : 1/4000Sec
ApertureValue : F14.0
ExposureBiasValue : EV0.0
MaxApertureValue : F4.0
MeteringMode : Spot
Flash : Not fired(Compulsory)
FocalLength : 120.00(mm)
ExifImageWidth : 2389
ExifImageHeight : 3539
ExposureMode : Manual
WhiteBalance : Auto
SceneCaptureType : Standard
Mike