If you want to chase your twitter avatar to green, but you don’t want to trust another service or program to do this, you can do it yourself. (Think of it like an arts and crafts project. 🙂 )
To do this the way I did, you need to have access to Microsoft’s Photo Editor and the photo that you used for your current avatar.
1) Open your avatar photo using Microsoft’s Photo Editor.
2) Click on “Image”
3) Click on “Balance”
4) Change the selection from “All Colours” to “Green”
5) Change the Brightness setting to “100”. The picture should now be green. You can play around with the brightness setting if you want.
6) Click on the “Ok” button
7) Click on “File”
8) Click on “Save As…” Give it a different name than your current avatar in case you want to switch back later
Now go to twitter.com
1) Click on “Settings”
2) Click on “Picture”
3) Use the “Browse” button to find your new green avatar
4) Click on “save”
You should be done!
If anyone knows how to do this with other technology like Mac OS X or Linux, please comment below with a link. Thanks.
Smart People I Know 
put an ubuntu live-CD on your PC and boot
1) Click on Application -> graphics -> Gimp
2) File – Open – your img
3) click on colors and choose green
4) Airbrush tool – 15% opacity and do the job 🙂
5 save … and sand an email to your friends
Sounds like a good Linux (Ubuntu) solution! Thanks, Luigi!
1. For OS X, open your avatar image with Preview.
2. Select Tools > Adjust Color
3. Move the Tint slider all the way to the left (the indicator should be green).
4. Save by selecting File > Save (or Save As).
Thanks, Victor and Luigi, for the advice on Linux and Mac OS!
There is a saying “Green with envy” 😉
Thanks for the comment on how to do it on the mac. I was trying iPhoto but now I’ll try preview.
Or you can just use this website…
http://app.helpiranelection.com/
yes, you can. and many are. as a rule, though, I don’t like giving out my twitter handle and password. while this site may be safe, it is not a safe practice in general to do that.