Images can be stacked on top of each other and though there can be 2 images horizontally, you can create many vertical columns of 2x1 pictures.
Click on the "Image Grid" option in your Biolinc "Create Link" menu.
In the pop-up box put:
Name the block (this will show up at the bottom of the block)
Add an Image URL (where your picture is located on the internet)
Add a Destination URL (where you want to direct your users when they click on the image)
Click on Submit and then see the preview
If you create multiple image blocks, you can stack them on top of each other in the builder (see below) and they will know their order in the builder preview. The image block placed at the top will always be on the left of the 2x1 grid. The one below will be on the right. The rest will alternate (left>right) again.