odintheking
Lighting the way...
I don't think someone has made a tutorial for this yet, and SoG wants some help on this topic, so I'll make one. It won't be very long, and I even circled stuff in red so it's easier, so we should have a lot more tech-makers out there. (I have chosen to do a "Pikmin" tech)
Now, the first thing you want to do is to go to Google and pick your ideal picture, if you have not done so already.
Then, copy it into paint:
After that, close up as much of the image as possible wihout taking away the core image:
Then, go to "edit" then "select all", then shrink up the image to 128x128 and 32x32:
Then, go to "Image" then "Attributes" to change the size to 128x128 pixels:
Now, do the same thing, but make the image 32x32. Then, import it into a program that reads pcx's (I use Wally) or paintshop pro, save it as a pcx, put them both into a zip or rar format, and post. It may seem a lot to do, but you'll get used to it. It takes me only two minutes to do a tech now. See how easy it will be.
PART 2 PALETTES
Ok, people have been doing techs and have questions about pallets. Here we go.
The easiest way is to paste the image into a tech with similar colors and save it as a new tech. It usually works. But, if you want perfect quality, or your image has way too many colors, you have to change the palette of the image to 256 colors. Depending on the program, there are different ways to do it. In GIMP for example, you go to Image>Mode>Indexed and put 256 colors. Usually fiddle around with the tabs and you'll find "Reduce colors" or something. We're not done yet, though. We have to change the last two colors to bright green and pink. (Or other colors you are sure are not in your picture. Pink and green are usually used. If you get a color that is in your picture, it will look funky in game.) If you don't do this, the colors in the last two slots will show up weird in game. So you find some way to edit the palette (Again, different in every program) just change the last two colors. If you overwrote another color in those slots, and parts of the tech are green and pink, just select the nearest color and fill them in manually. Have fun,
.
Edit: Check Plotinus' posts for palette, in-game and other issues concerning techs.
Now, the first thing you want to do is to go to Google and pick your ideal picture, if you have not done so already.
Then, copy it into paint:
After that, close up as much of the image as possible wihout taking away the core image:
Then, go to "edit" then "select all", then shrink up the image to 128x128 and 32x32:
Then, go to "Image" then "Attributes" to change the size to 128x128 pixels:
Now, do the same thing, but make the image 32x32. Then, import it into a program that reads pcx's (I use Wally) or paintshop pro, save it as a pcx, put them both into a zip or rar format, and post. It may seem a lot to do, but you'll get used to it. It takes me only two minutes to do a tech now. See how easy it will be.
PART 2 PALETTES
Ok, people have been doing techs and have questions about pallets. Here we go.
The easiest way is to paste the image into a tech with similar colors and save it as a new tech. It usually works. But, if you want perfect quality, or your image has way too many colors, you have to change the palette of the image to 256 colors. Depending on the program, there are different ways to do it. In GIMP for example, you go to Image>Mode>Indexed and put 256 colors. Usually fiddle around with the tabs and you'll find "Reduce colors" or something. We're not done yet, though. We have to change the last two colors to bright green and pink. (Or other colors you are sure are not in your picture. Pink and green are usually used. If you get a color that is in your picture, it will look funky in game.) If you don't do this, the colors in the last two slots will show up weird in game. So you find some way to edit the palette (Again, different in every program) just change the last two colors. If you overwrote another color in those slots, and parts of the tech are green and pink, just select the nearest color and fill them in manually. Have fun,

Edit: Check Plotinus' posts for palette, in-game and other issues concerning techs.