That's... definitely a step up. I'm not insulting your usual artwork or anything, it's just... the shading just makes the whole picture pop. What program did you use?
Photobucket. I had to use a scanned picture for a college class and I figured I might as well upload what I got for feedback. Glad to see that it wasn't a dumb idea. I plan to use this technique for future promos, but for the comic, shading is only used for dramatic effect.
SC: All right, shading! I like the composition, too. I see you ran into the white-outline/white-speckle problem when filling. One trick I like to use is to select by color and grow the selection 1 pixel (or grow 2 pixels and shrink by 1, which avoids encroaching on thick lines but eliminates small speckles). This avoids having to work, work, work erasing all that stuff by hand. Edit: To demonstrate, here's this image of yours, despeckled in this way. To avoid picking up the 'foreground' black lines, I bucket-filled the background with a random unused color, before selecting by color. (of course, you might already be doing this for your comic images, but I'll leave it here anyway, in case the tip helps anyone else.)