iPhoto stuffed my start volume

I am using an old G4 Power PC with OS X 10.4.11 and IPhoto from iLife 6.

The photos are stored on an external usb disk. For every year I created a folder with the according iPhoto Library. Today I wanted to check the photos from 2017.

When connecting this external photo storage hd today, it was first not recognized by the computer. After I solved the problem and started iPhoto, iPhoto imported thousands of jpgs from the last folder I had used (2017).

This could not be completed because disk space was running out - on my boot hd, not on the external storage. I could see the album structure of 2017 in iPhoto, but no pics at all and I don't know where this bloody machine stored all the files.

I really would like to erase that double stuff, because there are only 270 MB left on the start volume, but I can't see, where it sits. Finder is no help.

2nd problem is, iPhoto is not displaying other Libraries, instead it starts importing files.

Has anybody an idea, how to solve this mess? Would be great.

Rolf