Read the terms of service of any other photo site or online backup program: they make no promises regarding length of service or safety of your pictures. In fact, they all specifically refuse to accept any liability for your photos - and they all retain the right to terminate your account whenever they want. Several sites even go so far as to tell you to make your own backups!
At Swiss Picture Bank our unique pricing model and Level 5 Security system allow us to offer the first guaranteed long-term image archiving service. Here is our commitment to you: We promise to keep your photos safe for the entire term of the storage period you purchase. In the extremely unlikely event that we ever lose any of your pictures, we will pay you 30x the market value of the credits you spent to deposit them. We know that no amount of money can replace a memory, but we hope that this guarantee demonstrates how serious we are about the safety of your photos.
Swiss Picture Bank: 30 years or 30x your money back.