Question: what is desktop wallpaper size?
Answer: 1024 x 768, 1280 x 1024, 1920 x 1080 are pretty common to the best of my knowledge. But obviously the more resolutions you support, the more compatible your wallpaper becomes -- the drawback is that it requires more work for you. Normal wallpaper has resolution of 1024x768 and screen ratio of 4:3 .