I posted this on the Adobe workflow forum and had no response. Perhaps some of you can shed light on this for me.

I can't seem to get my head around this. Could use some help. I have multiple copies of many pictures in the elements organizer.

I have used Picasa to view all of my photo files and they do not appear duplicated on the drive.

I can't find where or how to dump the library and have the program recompile a new one. Not that I am sure it would not do the same thing.

My main point of confusion is that LR4 is a photoshop module or something. It has its own library or rather you pull photos from the drive directly. According to what I have learned, any changes you make to a photo do not change the actual image. It is a collection of instructions that are applied at output. Elements changes the image.
How do you use both tools on the same image?

Just a guess, but your duplicates may have differing file extensions (.jpg, .psd, etc) and Picasa might not be showing all of the variants. Search the directories from the O/S and verify what is truly there.

Lightroom 4 is a standalone program that is optimized for photography workflow. It includes a number of modules that help photographers ingest, organize, edit, publish and print their images. It integrates well with Photoshop as both are made by Adobe.

LR4 is a non-destructive (parametric) image editor. Here's some basic info on parametric editing, raw files and various other topics that you might want to explore. There's quite a bit to learn regarding image workflow - good luck!

http://dpbestflow.org/image-editing/parametric-image-editing

Paul
My Nikonians Gallery