I've created a newbies version of "How to backup your R-Pi SD card", to make it clear & simple for all of us
For my example, I'm using Windows7 & "Win32DiskImager" for this example, but i'm sure it's basically the same for the linux version.
Ok, so you have your Raspberry Pi distro running, Appz are installed and everything configured EXACTLY how you want it.
Now you should backup your SDcard for future use, in case it dies one day (believe me, it WILL die), and i personally hate re-installing everything over & over again ;-(
So, lets create a backup image of your R-pi system....
Plug your SDcard into your laptop/pc/card-reader and wait until Windows finds it etc etc
( For this example, my SDcard appears as E:\ )
Startup the "Win32DiskImager" program, Here's the opening screen:
Notice you will need to select which drive is your SDcard. in this case my SDcard is E:\
then click the NAVIGATE icon just next to the E:\ pulldown box, this will open a file-explorer window.
(Also note that the "read" button is not
available to use just yet).
Select a folder on your hard-drive where you want to SAVE the image file of your SDcard. In my example, i have a folder named "rpi_backups".
Also type in a filename of the image you're about to create, and click SAVE to continue to next step.
I prefer to always include the SIZE of the SDcard somewhere in the filename, which is handy later on when you have odd sized SDcards that may require partition-resizing after being restored.
( e.g. burning your 8Gb image onto a 32Gb card, you'll need to resize, so you can use the entire 32Gb )
Confirm the folder/filename are correct, and now you can click the READ button to start reading your SDcard into your (about-to-be-created) image file.
Here's my image file being written, almost complete at 95% ....
It will indicate "Done" when the image has finished writing.
....and that's it !
Now can play with multiple Pi-distro's, try new Appz and always be able to revert back to your original (preferred) Pi images
I hope this helps