Can I send encrypted pictures/video

Yes, Silent Phone allows you to send photos and videos of up to 100MB.

 In an active message conversation, use the (+) icon in the text field to launch the attachment menu. You can then choose from the different available options. For example, you can share an image stored on your device ('Gallery'). Once you have found the image or file, tap on it and it will then be encrypted and sent to your messaging partner.