How to find original iPhoto Album photos in Library (by Album content)

I have run out of Macbook space (OSX 10.7.5) and want to put all my photos on an external hard drive and share them between MacBook and iMac (no cloud please). I want to do this by "Album" name because that's how they are organized. I don't get the "events" thing in iPhoto, nor am I interested in the "Faces" stuff. Just simple file access is all I want.

QUESTION 1: How can I find the original photos after exporting by album? I want to delete these permanently from the Library -- from my MAC.

QUESTION 2: Is there a smarter way to get these photos onto my external drive than using "export?" And, is there a way to re-size a batch of files as opposed to one by one? I made all my camera photos the largest size possible, one reason I've run out of disk space. But to individually re-size would be impossible.

😊Note: I'm in a mess with photos. Have 20K on MacBook and about 25K on my iMac. There are 8 different iPhoto Libraries on my iMac, created by me in an effort to organize but I didn't know what I was doing and they are a total mess. My goal is to get them all into this hard drive from both computers then start all over again. But they need to be by album. I'm not an "Event" person -- doesn't make sense to me, so I've put all my photos in albums. When I start over I may not use iPhoto. Thinking of going back to Windows actually.