Most dentists I know transfer digtital images, that is x-rays and photos, using e-mail. This is relatively easy but is technically a problem. Standard e-mail does not meet privacy and security requirements. Also just e-mailing sends the basic image but does not capture the crucial data that should accompany that image, like patient name and the date. It is like mailing an old film x-ray without the mount. The mount has all the data written on it.
There are potential liability issues for every dentist however I believe that specialists such as endodontists who send and receive a lot of images need a better security compliant system. There are Internet based options that can solve the problem. More later.