For the final part of the walk cycle tutorial, we will focus on the back walk cycle. The same technique here applies to the front walk cycle, which is why I'm not doing a separate tutorial for it or including it in this one.
Like the side walk cycle, you begin by filming yourself or model walking away from and towards the camera. In an ideal setting, you would, again, have a treadmill, thus eliminating any problems with scaling. However, if you don't, it presents an issue: you get bigger as you get closer and smaller as you get further.
Instead of being able to keep the same rectangle size as you were with the side walk cycle, you're going to have to do a separate one for each frame. The trick to remember is to make sure your rectangle top and bottom both fall on the very top of the head and bottoms of the feet.
As you can see in the photo above, each frame is a different size. Not to worry, however, since the tops and bottoms are at the same point, resizing them all to the same height will correct the problem. In this case we are sticking with 70 pixels high. Now all your frames are the same height, but each has a different width. To solve this problem, we find out what the width of your widest sprite is.
Here we see that backwalk1.jpg, our widest, is 38 pixels wide. Now all we have to do is enlarge the canvas size of all the other frames to be 38, keeping the image in the center.
Now all your frames are the same size. At this point we do a quick check to make sure everything is aligned.
And finally, just as we did with the side walk cycle, we paste the head from the standing view onto each frame and trace the rest of the sprite from there, making sure that the head stays in more or less the same spot, although with front and back walk cycles, the head bob goes about one pixel to each side rather than up and down.