1) Unlimited. So you will keep a copy my 1000s of 10-20mb RAW files for 8 USD/Month ?
2) Unlimited part two: How about a x/dollars/month > NxGB of storage (Where N is magic:)? IE: Some transparency towards your margins? And accounts for those that don't need quite 100USD/Year worth of service? I absolutely see that having a treshhold makes sense, but to me 8/Month seems high.
3) Since you're probably not* actually unlimited -- who are your target users? Someone with 1000s of high quality jpegs? Someone fed up with picasa/flickr/etc ? Do you have an actual roof on bandwidth?
4) The scaling: Do you do it browser side (ie: most of the pictures are rather shoddy quality compared to custom scaled/cropped images?)? Some of it server side, some browser side?
5) Which formats do you support? (Jpeg2000, other high quality formats?)