Wrong date_time with EXIF 2.2

[Jpunt]

I'm developing an image-gallery and I want to sort pictures by the date/time the photo was shot. This seems to be working great using this awesome gem, but after digging a bit deeper I found out that a lot of photos are getting the wrong date. The only difference between them (as far as I can find) is that some photo's are using EXIF 2.2 and some are using EXIF 2.2.1. The 2.2.1-ones are given the correct date/time, the 2.2 are getting a two-days-delay. Opening them in some basic photo-software results in the correct date, but slight differences in EXIF-data:

http://jpunt.nl/tmp/exif2.2.png
http://jpunt.nl/tmp/exif2.2.1.png

Any ideas on this?

[remvee]

EXIF reader can not read PNG images.

[Jpunt]

I'm aware of that. These PNG's are just screenshots of two info-windows, containing the EXIF-info.

[remvee]

I'll need to original images to figure out what is wrong.

[Jpunt]

Correct: http://jpunt.nl/tmp/IMG_2821.JPG
Incorrect: http://jpunt.nl/tmp/IMG_2822.JPG

[remvee]

IMG_2822.JPG:
date_time = Mon Jul 27 10:50:21 +0200 2009
date_time_digitized = Sat Jul 25 13:32:15 +0200 2009
date_time_original = Sat Jul 25 13:32:15 +0200 2009

Apparently some application changed the "date_time" time stamp on that image after some kind of edit (adjusted contrast or something simular?). The original is still intact; "date_time_original". You should use that instead for the date the picture was taken.

[Jpunt]

ah great, I didn't know date_time_original was a method. Thanks!