The bottom of the above Image Panel block has a positive slope added to the bottom edge with no bottom margin, and the Image Panel block below has a positive top edge slope with no top margin. This is a Group block with an inner paragraph and a spacer block below to avoid the text area being partially hidden by the Image Panel below. Setting no margin ensures that there is no gap between the background of the Group block and the Image Panel blocks.
Welcome to image alignment! If you recognize this post, it is because these are blocks that have been converted from the classic Markup: Image Alignment post.