Higher resolution yes, not dpi. DPI is a print term, not a digital term. You want to draw you picture/comics at the highest resolution you can (my usual is 5 times the needed size. So 940 pix across for webcomics becomes 4700) then resized down in your drawing program on export. DO NOT allow a website to downsize it, you have the control for quality, not them. ANY half decent art program will do it better than a website upload. For actual artwork you want to print, go much bigger than that. like 50k+ pix. I usually go as large as I can because you can always make it smaller and lose resolution, you can't gain resolution. When you print something the dpi will determine the size (real size on the paper by the dpi) Once again, you can resize down, if you go up with a raster format, you will get tiling. That is the reason some use vector art. You can resize as large as you want and not get tiling. In your example of 1600x20000, that is the max resolution. Whether it's 75 or 1200 dpi, the size is the same. The difference only shows when you print. At 75 dpi the picture will be HUGE, at 1200 the picture fit on a piece of paper. And the 75 would look horrible. But the resolution is actually the same, 1600x20000, there is just less of them per square inch. 600 dpi does not hide more info in the resolution than 75 does, it's the same.