I have about 50 GB of photos on my hard-drive (a photo has about 3-4 MB, you do the math how many photos have I made). How to back-up them all?
The solution is very simple: use a Picasa Web account, linked to a Google Plus account. You can backup photos of up to 2048 x 2048 pixels. The number of photos you can upload is infinite, as long as they’re not more than 2048 pixels wide or tall. The photos can be either private or public.
Read my tutorial on one solution of mass-resizing photos:
How to batch resize photos using IrfanView? – Get a result now!
Prior to linking to a Google Plus account, the resolution is much lower, 800×800 pixels.
Details on this:
I have personally backed up my photo gallery of 50 GB of photos using this method (with 800 pixels photos, which made my collection about 6 GB big).
So, as a conclusion, as long as you use Google Picasa account linked to a Google Plus account, you can backup entire collections of photos up to 2048 x 2048 pixels. The collection can be made private.