How do I change my YouTube display picture?

Well I want to make a YouTube account and before I made that account I made an account with a different name and email for a test. I put a pointless video on for the test and everything went fine. But what I really want to know, is can I change the front...

I don't like the display thumbnail picture for one of my videos uploaded on YouTube. How can I change it?

I try to change my display picture, I can select picture, when I click ok, It dont change my picture. it goes back to my old picture. What should I do to change picture?

I have been trying to change my display picture on Yahoo Messenger but its not changing. I have tried everything. (Please don't give me a crap like putting Jpeg image on the display picture or staying in available status or something related to 360 account...

I went to change the display image from an avatar to a picture. I accidentally put the wrong picture as the image. I went to change that picture, but it won't change. How can I change the picture? I am using Yahoo! Messanger for Mac.

It's been 3 days and everytime i make a status on facebook it dissapears and its not there on my wall. And everytime i upload a new facebook picture it sticks to my old one. I've deleted the picture but it's still there, when i press change the display...

I choose from right clicking on display picture and choosing new picture and clicking OK, then I went to menu drop down , choose new pic and choose OK and still no change in my display picture? Any suggestions?

i'm trying to change the heads up display to a different picture instead of a grey back ground. so when i'm on a site i can just push F8 and the screen will change to say the (desk top picture). I've tried the widget cover me but the screen shot won...