Some of you may recall the sprinting template I was working on for Mack's Loose Leaf sprite generating resources. It is now complete, and it's looking good when tested at running speeds. At walking speed it looks very choppy as one would expect it to.
Here is a sample of a sprite I took and made a sprint sheet for. I'm not to sit here and tell you it's a quick cut & paste job. It takes some work to adjust certain parts to match the new limb positioning, but I have some tips to make it much smoother.
This is the template. On the left you have the standard walking sheet, on the right is the sprinting edit.
I suggest assembling your walking sprite as you normally would using any image editor like Paint.net, for example. Keep the project file with all layers separated. You'll use this to transfer layers one by one to the sprint template to edit and position them to your liking, retaining all edits and color selections during this process. So the clothing that you apply to your sprint template, is the exact same as the clothing on your walking template.
This makes it much easier to create the running version of your sprite. I suggest starting with the pants and feet, working up to the body. I actually separated the sleeves from the body of my sprites undershirt to make that process easier and a bit more painless.
Credit only to Mack. I don't share my edits for personal credit.
Enjoy! Don't be shy reporting in errors/bugs.