For the third Text Color, choose the same color you chose for the previous text.
If we must use the same color we used for the previous text color, it is easier to just copy and paste the previous color's item code number (the short phrase beginning with a hashtag).
The ideal aspect ratio is 3:2. When the image width is 200 pixels, the height should be about 133 pixels. If your height value is substantially different, crop the image to avoid distortion in the thumbnail.
I noticed that it's blurry, at least for me, when I use paint for this. Rather, I used my computer's default app; snipping tool, and uploaded it onto http://resizepic.com/ to resize the image into exactly 200x133 pixels and it was not blurry.