How to PERMANENTLY delete a photo from iPhoto?

After deleting from iPhoto and emptying the iPhoto trash the files should go to the System Trash. Empty that too.

If that doesn't work then the library is corrupted, so rebuild it:

IDownload iPhoto Library Managerand use its rebuild function. (In early versions of Library Manager it's the File -> Rebuild command. In later versions it's under the Library menu.)

This will create an entirely new library. It will then copy (or try to) your photos and all the associated metadata and versions to this new Library, and arrange it as close as it can to what you had in the damaged Library. It does this based on information it finds in the iPhoto sharing mechanism - but that means that things not shared won't be there, so no slideshows, books or calendars, for instance - but it should get all your events, albums and keywords, faces and places back.

Because this process creates an entirely new library and leaves your old one untouched, it is non-destructive, and if you're not happy with the results you can simply return to your old one.

Then trash the old library.

Now delete them from the new library, do they go?

Oh dear. You've just trashed your iPhoto Library. All your high quality originals been replaced by lower quality previews. Really, that app is lethal to iPhoto Libraries and to Macs in general. Get rid of it. I hope you have a back up. Do you really thing that almost half the data in the iPhoto Library is waste?

No really? So what was that missing data? Why is the Preview smaller? Still whatever works. You might want to ask then why you're using an app dedicated to a non-destructive workflow if you're going to trash the library to convert it to a destructive workflow. Be simpler to use another app really.

I double checked size of the duplicate files before deleting it. For comparison: file A (original) 2.2 Mb. and file B (modified) 1.9 Mb. I don't think I lost files with better quality.

It is no longer the original. The iPhoto previews are new jPEGs derived from the original. The JPEG compression is lossy, otherwise the file size would not decrease. You will notice slight differences along the edges, maybe some JPEG artefacts.

It will not matter much, when viewing the image, but subsequent edits will not be as good as from the original image, for example edge sharpening.

First, I am not trashing the library.

You've just annihilated the non-destructive processing feature. From now, all further interactions - edits, exports, sharing, printing - will be based on the lower quality preview. Not sure what you call that, but that's removing a major feature of the iPhoto Library, pretty much the entire point of the Library.

Supposedly, preview version of a file is smaller because of cropped area.

No it's not, though that will be a fraction if it. As Léonie explained, JPG is lossy, so more data has been thrown away. It happens every time you edit and save a JPG. Back to that non-destructive processing thing again.

Second, I am not advertising this tool, I just mention the way one can benefit from using it.

Yes, but there's a courtesy here: when you suggest a course of action that causes dataloss you should point that out.

You might be surprised, but I'm not questioning the usage of non-destructive app.

But you are... See above.

Regarding the missing files: during cleaning procedure they were also detected as original files without duplicates. I deleted them long time ago and I have no idea why they were still remaining in the library.

Because you're library was corrupted. Which is what we were working on fixing. Non-destructively.

y the way, pardon my ignorance, but why do you think this tool is dangerous to Mac? Does it do something with system files?

Search the forum for the many, many threads from folks who had had major issues after using the app. Remember, your Mac doesn't get "dirty", it doesn't need "cleaning".

Léonie, where are the original files? I thought they're stored in the Masters folder.

They are, unless you let "Cleaning" apps interfere with the iPhoto Library.

CleanMyMac2 deletes the original from the Masters folder and replaces it by the preview of the edited version. iPhoto will now use the edited version as a new original file. When I tested this, I found that this surgery was implemented incorrectly, for some of my images the new "Originals" were wrong and some of my photos lost completely. Perhaps this bug has been fixed, but I I am glad I tested only on a redundant test library.