Cross-Gutter Links is a complex aspect that the artist uses to keep scenes going from one panel to the next. They are right next to each other and usually the same, square size. It calls for scenes that there is a call to an action where the background seems to continue across the panels. The examples below will help to explain better.
Figure 1 shows the classic example of cross-gutter links and the easiest way to explain. Casper is trying to find someone and is scaring everything away. Each panel on the left is a call, and the panel on the right is the action. He is going to look in the lake for his friends, the fish all run away because they are scared. The bottom row Casper is shown walking into the cave and then panel right after has him talking while in the cave. The actual cross-gutter link is when looking at the first row, we see the water. If you were to continue the water to the next panel, the water would match up perfectly. It works with the other rows too if you look closely. The second row has the puddle looking think around the mushrooms, and the next panel has a puddle around the rocks.
Figure 2 is a more obvious example of cross-gutter links. It a scene from Steve Englehart, Detective Comics #475. If you look at the panels, you will see that each one goes straight into the one next to it. The curtains starts in the third panel on the first row and in the next panel you see the rest of it. It keeps the readers attention to detail alive and is able to keep the scene going. It gives the allusion that it is one panel but in reality it is two.
Figure 3 is the last example of cross-gutter links. It shows the links between the clouds of each panel. It has the basic layout of rectangle panels that are similar size right next to each other. When looking at each panel, if you were to take away the white space in the middle, you would have a single row of clouds that are all connected. That is what cross-gutter links are, the line you can make in the white space to connect the panels.