[dosraider]

As I begin to know you, you seem to have forgot an important thingy:
Must be free of charge.

And that's the problem I'm affraid for what you ask.
A 100 % sure way of storing your files for free on a webserver, mmmm, nope, not really.

If you want to pay for that service, yes, plenty reliable providers of those around, and if you pay enough they even backup all your files, twice or triple, on several HDs for security, but not free of charge.

For what it's worth:
I have several (damned even whole pile of them) ISOs stored on GMail, never let me down t'll now.
If you want (or need) an invite just say so.
Drawback on GMail: when you provide the link you also must give the passw for that account, so ...... don't really think it's interesting for you. In fact you can only share those with people you trust.