Hosting solution for images for website written in PHP

I've written a website in PHP and it will have ability for users to upload images. My website will have more than 100.000 users. Aprox. 1k users will upload image about 50 KB. And every image will be displayed on this website 5k times so it's transfer of:

1k x 50 KB x 5k = 250 GB per month.

So my question is:

Do you know any good solution (hosting or CDN network or else) that:

• will be payed for开发者_StackOverflow transfer not space used and no entrance fee
• will have API to upload images easily with PHP
• is extremely easy to use
• will be good for low budget
• will not require any special, complicated registration and formal things
• will allow commercial use
• will allow using this images in website layout

?

Gonna make my comment into a proper answer.

From what i see the image storage is probably trivial compared to the site traffic and application load. So you use the cloud sites from Rack Space for your PHP application and pay for extra CPU usage according to traffic, application load. If you need specialized solution for storage you can use Cloud Files as an addon and the integration should be pretty straight forward.

Amazon S3 nearly meets those requirements.

I think the only one it fails on is that it has a storage charge (a small one) in addition to a bandwidth charge.

Windows Azure Cloud