In the libary of iPhoto I do have double pictures only in the year 2006. Can someone please tell me how to remove the double pictures. I did rebuilt the libary but that solution did not help me any further.

Question

In the libary of iPhoto I do have double pictures only in the year 2006. Can someone please tell me how to remove the double pictures. I did rebuilt the libary but that solution did not help me any further.

Answer 1

I think the warning is very clear.
What warning? Where do you say that this plan you suggest will lose at least some, and possibly a whole lot of metadata, plus  the original files of edited photos. This is significant dataloss. And you should warn people that this is the case.
While your metadata and originals may not be important to you, that is not necessarily the case for other users.
Fourthly, and last, cleaning the iPhoto library should be done at least once per year
This is nonsense. The iPhoto Library has no need of "cleaning" and certainly not in any way that trashes a whole lot of data.
I'm very impressed that you assess the application based on the sound of the name. It's not a common way to review applications, but I'm sure it has some merit.
FWIW it has been recommended on this - and other - sites for many years and has proven safe and effective.
Regards
TD