RGB JPEG, - 1920X960 Pixels - minimum text height of 40 pixels
Also we recommend avoiding Full White for large areas of the background (ie logo in centre with total white behind) as the full white can distract from the message.
RGB JPEG, 2 parts | side one (left) 1080wX960h pixels - side two 1560w960h pixels - minimum text height of 36 pixels
These 2 join at 90 degree angle around corner.
With this site images can wrap around corner but each side needs to be “complete” ie a message can't continue around the corner - ie if someone sees just one side they need to get the full message.