TL: DR Version: Glad you like the Coco pic! I like to at least have a Rough Sketch before painting anything. However, I rarely bother with finished line work though, as I typically just paint over it and have since stopped making fully rendered line work because of that.

Long Version – Just in case you wanted to know the process in a little bit of detail

I'm glad you like the coco pic and you're kind of right. I don’t use finished line work for what I paint. However, unless I already have a really good idea that’s really simple to paint, I will normally make a few thumbnails and then make a rough sketch from the thumbnails that I think are interesting. That way I'm not attempting to make a full painting of something that I'm not sure will work or finding my self having to edit stuff halfway through the painting. After the rough sketch, I choose one of my three usual methods to paint based on what I’m trying to achieve:

My preferred method is to paint in grayscale first and then color over it. This is my preferred method because it makes me focus on shadows and highlights and on the form. Below is an image link to the steps and a video of me painting a Sally image starting with grayscale then working in color after getting the shapes down. In the Tawna Video below it, the method is the same, but instead of painting the shapes with a brush and doing all the grayscale work first, I made use of line work to make easier fills and then paint over them. This is also the method I used to paint this coco image.
-Tutorial: https://www.newgrounds.com/art/view/7los7/amy-rouge-color-shift-tutorial-shading-first
-Sally: https://www.youtube.com/watch?v=iN4sBrPBWA0
-Tawna: https://www.youtube.com/watch?v=ZIm8H-nbznI

If I already have a color sheet on hand and/or don’t plan on having a lot of detailed shading, I will block out color first and then do some simple shading on top of it. Most of my Rouge the Bat Images are done this way as I’ve drawn her so much that I normally just pick whatever colors I think will work for her.
-Tutorial: https://www.newgrounds.com/art/view/7los7/sb-pin-up-process-color-first
-Rouge: https://www.youtube.com/watch?v=Zxd_QqvabAI

As for just painting directly to the canvas, it’s my least preferred method but I use it when I’m attempting to get a “painterly” look, like in the new Scanty image I uploaded. I’ll be uploading a time-lapse of me painting that in the future after I am able to find time to edit down the video. To me, it’s the hardest method because you’re working with both color and shadows at the same time and normally you’re working on only one layer or as few layers as possible to maintain the “painting on canvas” effect.

While any of the three methods work for me, thumb-nailing and making rough sketches first will help you come up with many ideas at once and will help you refine what you’re trying to achieve. Not that painting straight to the canvas from what you’re envisioning isn’t a valid way to paint, I do it from time to time as well and it takes a lot of skill to do properly. But it’s far easier to edit a sketch then it is to edit a fully rendered painting that is all on one layer, and while editing a finished work broken down into layers isn’t as easy as editing a sketch, it’s easier than the full painting. But then again you could always just paint over it as a traditional artist would.

But this is all really just my personal opinion and methods of doing it. I was going to college to work with typography and web design before being any sort of painter so making rough drafts and sketches before making a final piece has been drilled into my head over the years. I’m pretty sure other artists have different methods and opinions but sketches and rough drafts are useful when you want to make something, especially if you’re making something for a client. Again, really glad you liked the pic and if you’re interested in learning how to remove line work from your paintings I would suggest checking out Ctrl+Paint’s tutorial on it. ( https://www.youtube.com/watch?v=xDSpRVUapN4 ) they have a few other tutorials that I found to be helpful when I was getting started.