If you use Windows, you can open your Paint application from Accessories, select the text tool, and cut and paste the Chinese text into the text area (make it big enough).
If you have difficulty doing that, you can use Print Screen key to capture the screen and paste it into Paint and save it as .gif file.
Or you can install the freeware
http://irfanview.com/ , run it and just copy and paste Chinese text into it and save it as gif. (I like this myself because we use juse only two color to have small size of .gif file) Tip: you should manually wrap the Chinese text before you paste into IrfanView to make it look good. IrfanView has many great features for you to create great images.
If you use Mac, you can do similar screen capture and paste it into an image editor to save as .gif.
Good luck.