I totally know what you mean about the DD's. I got a DD on a crappy old tutorial of mine, while I had extensive flash-based tutorials that seemed far more applicable, however in your case, I can see why this got a DD before your perspective ones. While the perspective ones were well done, the information can be found in any perspective textbook or beginner's drawing book (I don't mean that in an offensive way, hopefully you understand what I mean) whereas something like THIS is so hard to come by anywhere!

This is that sorta thing you learn in school, or on the web, where people say "save JPGs for photos/colorful images, save PNGs for web." but no one ever says why or breaks it down like this. Prior to this, I was really confused as to why I would try to save my webcomic pages as a PNG only to find that a compressed JPG was better quality AND smaller filesize. I guess what it came down to was the fact that I used a lot of gradients in my webcomic, does that sound about right?

So am I to assume, that say, a cel-shaded pic like this [link] should be saved as PNG24, whereas a gradient image like this [link] should be saved as a JPG (for web, that is)? Because that was something I struggled with, when trying to get my webcomic pages to the smallest size for web, while still maintaining the quality.