How does one capture & copy a single frame image from YouTube?
I want to use it as a wallpaper on my desktop.
The long and very crude method would be to pause, press print scr, paste it into Paint, then erase all the stuff you don’t want. If you view it in full scree this will make for a lot less erasing. Pressing alt and print scr will take a picture of just the window, no bar on the bottom if you’re not in fullscreen.
If you do it in fullscreen you may not even need to paste the image into Paint at all, just find out where your computer saves individual files on your clipboard and cut/move it somewhere else so you can find it in the future.
Use the “Print Screen” key on your keyboard to capture the frame.
Open Paint (or IrfanView or some graphics handler)
Past the image (it’s on the Clipboard) into the graphics handler
Crop out what you don’t want to keep
Save it as a picture.
Thank You. 
The pictures on YouTube can be a bit blurry, due to the conversion from a photo to a video.
You can try finding the original image. Screenshot the YouTube video, clip the image so that the photo is central, then save it.
Then go to http://www.tineye.com/ and upload it
That website is a reverse image search engine. You can upload an image there and it’ll attempt to find other similar images. It’s good for finding original images, or larger ones.
My work computer has a program called Snagit, which lets you define and capture any rectangular portion of your screen, and it’s ridiculously simple to use. I just tried it out on a paused Youtube image and it worked great.
Looks like it costs 50 bucks, but there’s a free trial available.
I like Jing for screen captures
Why on earth would you use an erase tool when you could instead use a cut or crop tool, which would take only a second *and *give you clean edges?
You could download the video from youtube (.flv extension) and open the file using VLC media player. In vlc you can pause it at the picture and there is a screen grab tool built into it.
I use an addon in firefox to download youtube clips. I can’t recall the name and I’m at work at the moment. I will try to post it later.
If you have a PC there should be a “Snipping Tool” in the Accessories menu that is a lot easier to use than prt-scrn.
While this doesn’t help the fact that stills from YouTube can be blurry, I’ve found that if you pick the “frame” (as it were) carefully, you can get a clearer still.