Is my comparison right?

[Voodoodream]

I have 2 picture folders and one has some newer pictures in it than the other.
I compared both and comparison result tells me, that all my pictures are new and are missing in the other folder. That is not correct. There are picures existing in the other folder which have the same size, the same content but different names. So when I compare content it should result in some identical files (content) and some different files (missing in other folder). But all comparisons bring the same results, that all my files are different and need to copied into the other folder.

But when I compare the 2 folders in FreeCommander, then I see identical files with same sizes and dates when the photo was taken and content but different names.

Did I do something wrong in the comparison dialog window?
Does anybody have an idea, how I can get a result which tells me which files are actually not yet present in the other folder so I can copy them over?

Thank you all so much for your help!

1 attach the comparison result from filesync and 1 screenshot of both folders in freecommander with one selected file (example) which I checked and the content matches on both sides.

[Plerry]

First of all a warning:
Your FFS Compare result screenshot shows you are using the Mirror (Spiegeln) sync variant.
Apparently your left-location comprises 339 files that FFS (thinks) do not exist in your right-location, but conversely, that you right-location comprises 48350 files that (FFS thinks) do not exist in your left-location. And that, because you use the Mirror sync variant, FFS intends to delete those 48350 files from your right-location!
If that is not your intention, you should probably use the Update (German name?) sync variant instead.
So, be forewarned!

Regarding your actual question, I have just some clues:
You are Comparing by file-content (Dateninhalt).
The fact that files exist on both sides (as you FreeCommander screenshot suggests) does not necessarily mean the file-content is identical. Even if the file-size of files is identical, their content can potentially be different. Some software or tools have a nasty habit of modifying content, e.g. meta-data, without you being aware of it.
I also noticed (in the FreeCommander screenshot) that the file-modification dates (Geändert am) left and right are different, which is most of the time is not normal (and may be a clue).

[Voodoodream]

Hi Plerry.
Yes, I just wanted the missing files to be added to the main folder with all my pictures.
Thanks for the warning! I thought if I choose mirror from left to right that it will add the missing pictures. But I do not intend to delete all other pictures :) So I switched to update :)
The content problem is strange though. It is the same picture with the same content when you open both files. But it is not recognized as the same. So it must be your guess with the meta data that must be different in the files. I had to switch the app on my mobile phone to upload files to my nas. So maybe the first app did rename and store different metadata into the files than the new one. The new app "found" the same pictures (some already were uploaded by the old app) on the phone and did it somehow different. But since the switch to the other app new pictures were added and I wanted to store these only and skip all other pictures. It seems different if FFS cannot differenciate the files and tell which ones are duplicates and which are new. ???mmhhh. Am I out of options here?

[Plerry]

If only more recent files need to be compared and synced, you could try the time-span filter-option, which can be found in the Filter Settings (F7).

[Voodoodream]

Thx Plerry. Good idea. I tried the time span with the last 60days. It made no difference in detecting duplicates. FFS found all files needed to be copied and did not recognize any of the existing files. Mhhh..

[xCSxXenon]

Files with different names are always considered different by FFS. FFS is not a duplicate finder

[Voodoodream]

Dear xCSxXenon. Thank you for your input. You're right. I did not think of that. I will use FFS for sync only. That is what it is made for.