Direct linking to your pictures is allowed in the subscription version of ImageShack, according to their TOS.
I pay $2/month for unlimited use. They may have raised that rate, as I subscribed when it became a pay only service as a long time user.
Free storage clouds usually don't allow direct linking, although you can still do it - the chance your photo would attract enough traffic for them to notice is rather low if it isn't kitty porn.
Pic Posting
