iPhoto is pointing to thumbnails, not full pix

I'm still working on iPhoto '08. 7.1.5.

I find the multiple kinds of photos when I open up the photos folder. I don't really understand the internal structure, but there appear to be full-sized photos in there, data folders, and thumbnails.

It takes me to a photo file in the photo folder that is of the size described in the iPhoto program. But I can see other versions of the same photo inside that folder — some of which are full-sized.

In a few cases I have multiple versions of the same image in iPhoto: One will be low-res, and I right-click on it and go to the low-res original. Another will be high res, and I right click and trace it to a high-res original.

[Are these "original files" considered part of the iPhoto library and therefore untouchable? I thought maybe the thing to do would be to re-import the high-res versions, and delete the low-res ones from inside iPhoto.]

No, the originals are not low-res; that's the crux of the problem. Photos that once appeared in iPhoto as high res are not high-res. Yet high-res originals appear to exist.

I don't recall the steps that Apple walked me through when I had some library problems and we reconstructed them--so I can't answer your last q.

Here's a (possibly) clarifying example: In one instance, Iphoto presents two sets of one "roll" of shots, seemingly identical. One set is low res. The other is high res. In one case, the program seems to be pointing to the original photos. In the other, it seems to be pointing to thumbnails.

I'm hoping that's the case for some of the other photos: that the program is simply pointing to the wrong set of photos, and that the high-res versions are still in there.

In the case I just described, yes: There are two sets of identical photos visible in iPhoto, but one is high res, one is low res. "Show file" reveals two different sets of photos in the library, one high res, one low res.

It will take some searching to see if the low-res photos in other cases (without high-res counterparts in the iPhoto viewer) have high-res duplicates in the library. I do notice that in many cases the library keeps a full-size copy and a thumbnail.

The more general point is that all of these photos were taken with a high-res camera. (Except a tiny minority taken with an old cellphone.) So I fear something got messed up.

I may need to hold off till this weekend till I have time to more fully investigate. (I have two situations: Duplicate copies of some photos in iPhoto, with one set on the order of 2MB in size, each others 20K. In the other situation I have a bunch of 20k sized pictures that I know were taken at a higher resolution.)

I don't think I did such a thing (or know how to); I did have a large problem with iPhoto a couple of years ago and an Apple helpline staffer walked me through rebuilding the library. My wife has been accessing iPhoto from a networked computer; maybe that introduced some garble? I don't know.

Okay, here are the further steps I've taken. I did venture into the Pictures folder--frowned on, I know--to see if larger originals existed of the 19kb-size photos in iPhoto.

I found that by previewing those photos, you could see if the photos had been imported into iPhoto; if they hadn't, you could click a box and important them. Many of my high-res photos were not imported, for whatever reason, so I did so, one by one. Tedious but hopefully productive. I did not touch anything else in that folder.

But I do also seem to have a two-libraries-file problem. (This may be the result of the Apple Care call I mentioned earlier, in which someone walked me through reconstructing a corrupted library by creating a new one.)

I have a libraries file called Newlibrary, and another called iPhotoLibrary6. Both have been updated in the last day.

Is the recommended next step to merge these, using iPhoto Library Manager?

I thought I could merge the two libraries, but LarryHN seems to have diagnosed the problem: iPhotoLibrary6 is located inside NewLibrary (and inaccessible to iPhoto Library Manager), and there are many duplicate photos.

What's the best way to undo that mess?