<a href=showthread.php?s=&postid=15350391#post15350391 target=_blank>Originally posted</a> by mpoletti ... where did you find that out from?
Every .JPG image has imbedded information (the EXIF) about the exposure, etc. Special utilities allow you to access the info.
BTW: if you're interested google OPANDA. It's the name of a free utility to view EXIF info. Once you install it (you want to download the free IEXIF version of the util), right clicking on a .JPG image adds a "VIEW EXIF" item to the context menu. It's very practical. I use it a lot to get a feel how others have managed to capture difficult subjects. I can vouch for the SW. It's widely used and comes from a well known company.
Here's the info from your image:
Make = NIKON CORPORATION
Model = NIKON D90
Orientation = top/left
Software = PictureProject 1.7 W
Date Time = 2009-07-05 08:28:49
[Camera]
Exposure Time = 1/80"
F Number = F1.8
Exposure Program = Shutter priority
ISO Speed Ratings = 450
Exif Version = Version 2.21
Date Time Original = 2009-07-04 19:15:35
Date Time Digitized = 2009-07-04 19:15:35
Shutter Speed Value = 1.8 TV
Aperture Value = 1.7 AV
Exposure Bias Value = -0.67EV
Max Aperture Value = F1.74
Metering Mode = Pattern
Light Source = unknown
Flash = Off
Focal Length = 50mm
Maker Note = 114 Byte
Flashpix Version = Version 1.0
Color Space = Uncalibrated
Exif Image Width = 1024
Exif Image Height = 680
Sensing Method = One-chip color area sensor
File Source = DSC
Scene Type = A directly photographed image
[MakerNote (Nikon)]
Makernote Version = 0210
ThumbOffset = 108
00A2 = 680328
0E05 = 2
0E10 = 202
I should mention that some images, if they have been modified for web display will have had the EXIF stripped out.