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Puzzled - 2 'identical files' having 2 different file sizes


#1

Downloaded some photos from my (very) old Nokia.
Some I had already downloaded in the past and renamed them, adding a leading word Nokia to the filename.

When checking, I noticed that some of the downloaded images are having difference in file size compared to the existing ones, i.e. the ones that haven been downloaded in the past.

No big deal: it involves just a limited number of 'duplicates', all in the same folder, so they are quickly cleared.

Nonetheless I am curious to know why these files are different in file size.

In theory it could happen with hundreds of files and stored in my subfolders, i.e. removing duplicates (based on file size) may be more complicated.

SnagIt-01012019%20101621


#2

Does this involve Opus at all?

There is no way for us to tell you what is different between the two files without copies of the files.


#3

No, I agree, it does not involve Opus.
Just hoping someone would have a clue. Forget it, it is not a big issue in this case.


#4

Is it possible that one of the copies has associated metadata?


#5

Yes, it's very likely caused by added metadata. I have made the same observations with pictures from Nokia phones.


#6

That is also what i would guess. Some copy tools will strip (or don't support all) metadata.
Also some tools when copying from devices will re-compress the JPG, also adjusting the file size (even if it keeps the resolution the same).


#7

No - same photo - I forgot I already downloaded those photos and re-downloaded them.
Downloading: mobile phone connected to pc using USB, then using Opus to copy them from mobile to HDD.

I did some further checking using ExifToolGUI - see below
ExifTools shows differences.
Modified, Created, Access date and time stamp = all the same. No doubt, if I were to modify the photo, in whatever way, resolution, date/time stamp should change along.

Thanks for the replies. I'll delete those duplicates, not a big number.


#8

Maybe, but maybe not depends now how and what app.

Looking at the metadata you can see that the nokia-foto file has extra meta data fileds. Specifically
some photoshop, and has an IPTCDigest value. When Photoshop added this metadata, it modified the file, but appears to not have updated the modified timestamp.

Anyway, looks like the extra size was just metadata, added by photoshop.