Huawei P20
It's not possible to send and receive picture messages
Solution 4 of 5: The picture message isn't written correctly
A picture message is a message which can contain pictures and other media files and can be sent to other mobile phones. If you can't send and receive picture messages as soon as you've inserted your SIM, you need to set up your phone for picture messaging.
Press the message icon.
Press the new message icon.
Press To and key in the first letters of the recipient's name.
Press the required contact.
Press the text input field and write the text for your picture message.
Press the attachment icon.
Press the gallery icon.
Press Gallery.
Slide your finger right starting from the left side of the screen.
Press Images and go to the required folder.
Press the required picture or video clip.
Press the send icon when you've finished your picture message.
Press the Home key to return to the home screen.