Booth2 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.
To set up Photo to Phone go to the Settings tab and check the box for Photo to Phone to enable. Then click on the button next to the check box. In the setup dialog you can set the following options;
Select the provider. Currently only Twillio is supported. If left blank it will use the email option where the user selects the carrier. You must have a send email account set up for this option.
Select the file size to be sent. For most phones medium will be the best option.
You can also add a separate template that will be applied. This option will allow a different template than the default. Such as one formatted for the phone screen instead of the default strip. If left blank it will be sent with the default template like the print.