Hello essenzza,
From your question it sounds like you are trying to locate pictures that you've recently imported to iPhoto. And, you want a backup strategy that includes a second copy of your images on an external drive.
Have you updated your MacBook to OS X Yosemite? If so, the pictures you imported into iPhoto can be accessed from the new Photos application.
Get started with Photos for OS X - Apple Support
https://support.apple.com/en-us/HT204655
You can continue to use your iPhoto application, and if you want a backup of the images in a folder and not packaged in the library, then you will need to export your images from within the iPhoto application to folder(s) on your external drive.
I agree with you wholeheartedly that a second or even third backup of your photographs is extremely important. Personally, I import my pictures to the Photos application and have iCloud Photo Library enabled so that the images are in the cloud. If you don't have iCloud Photo Library enabled, then your iCloud backup will include your images.
I also use the Image Capture application to make another backup of the images I've taken with my iPhone or camera to an external drive.
Here are a few resources we have for importing and backing up photos:
Import photos and videos from your iPhone, iPad, or iPod touch to your Mac or Windows PC - Apple Support
https://support.apple.com/en-us/HT201302
Image Capture: Transfer images and other items from your device
https://support.apple.com/kb/PH17894?locale=en_US
iCloud Photo Library FAQ - Apple Support
https://support.apple.com/en-us/HT204264
The number of photos and videos you can store depends on your available iCloud storage. When you sign up for iCloud, you automatically get 5 GB of free storage, and several iCloud storage plans are available from 20 GB for $0.99 up to 1 TB.
No. After you enable iCloud Photo Library, your photos and videos are automatically uploaded and stored in iCloud. They won't be duplicated in your iCloud backup.
iCloud Photo Library stores all of your original photos and videos in iCloud, but we always recommend you keep back up copies of your Library. You can download your photos and videos from iCloud to your computer and store them as a separate library, transfer them to your computer with iTunes, or store them on a separate drive.
Your photos and videos are important. Even if you use iCloud Photo Library, it’s recommended that you use Time Machine to back up your Mac, including your Photos library.
Keep your Photos library and Time Machine backups on different disks. An easy way to do this is to keep your Photos library in your Pictures folder (the default location), and set Time Machine to back up to an external drive, a disk on your network, or a Time Capsule.
essenzza, the Finder application is your main tool for copying or moving files between your computer and external drives. You can search Finder by file type to find all of your images. Here is some information on the Finder application:
OS X Yosemite: Folder basics
https://support.apple.com/kb/PH18762?locale=en_US&viewlocale=en_US
Regards,
