Hi Tracey!
It sounds like you're looking for more control over image size and placement when authoring in Rise 360!
I'm happy to share that we are tracking a feature request to give authors the ability to resize and arrange images and text within a layout. I've linked this discussion to the feature report and will provide updates if it makes it onto our Feature Roadmap.
Also, you had a smart idea by inserting blank images in the four-column grid block, however, that will affect the mobile view of the lesson. I'll open the floor to your fellow community members to share other ideas with you!
