Imagebin is a place you can simply upload an image to. It lets you upload your image, then provides a convenient URL you can share with whomever you please, through e-mail, social networking or even in person.
Simply select an image to upload, select the Upload to Imagebin button, and it will return a URL you can share.
Basically, in trying to keep this service free for general use, there are a few limitations.
Imagebin is a fairly expensive service to keep running, so if you enjoy using it, please consider donating.