Darkroom Booth allows direct uploading to a phone by text message in two ways. One requires an outside service called Twillio. A Twillio account will provide a phone number that the images will come from. You can get more information about
Twillio here. The second way does not require any outside services and uses your email account to send those messages. The difference to the user is if you use Twillio they only need to enter their phone number but with the email option they enter the number plus select their phone carrier like AT&T, Sprint, etc. Most major carriers are per-configured but the list is editable so you can add or remove carriers that are not in your area.