File difference... old pic changes file size

[Qacer]

I was doing my usual backup routine and noticed that some pictures from several years ago suddenly changed in file size. It seems like the change was just recent, April 2013. I had backup these pictures to an external drive, and at least once a month, I run the backup to synchronize what's on storage to what is in my main drive.

Report generated from WinMerge:
http://miso.comli.com/picture-difference-report.htm

Picture of file difference from SyncBack:
http://i.imgur.com/UWPArVU.jpg

I have not edited any of the files. The only thing I've done is open them up in Picasa just to look at them. I also updated Picasa recently.

Any idea what caused my files to change in size?

O/S:
Windows 8

 

[unokitty]

I was doing my usual backup routine and noticed that some pictures from several years ago suddenly changed in file size. It seems like the change was just recent, April 2013. I had backup these pictures to an external drive, and at least once a month, I run the backup to synchronize what's on storage to what is in my main drive.

Report generated from WinMerge:
http://miso.comli.com/picture-difference-report.htm

Picture of file difference from SyncBack:
http://i.imgur.com/UWPArVU.jpg

I have not edited any of the files. The only thing I've done is open them up in Picasa just to look at them. I also updated Picasa recently.

Any idea what caused my files to change in size?

O/S:
Windows 8

If your backup device uses a different sector, or cluster size, that would explain the difference. See:
http://en.wikipedia.org/wiki/Data_cluster

Uno

 

[Ketchup]

So am I reading it correctly that the files are actually being saved as smaller files? Is this really the first time the files showed as changed sizes, or just the first time you noticed? Are the files actually smaller when reaching their destination, or does the program just say they are?