Best method for taking screencaps?

I’ve got the Season 1 DVDs, and when I put one into my computer, all that I can get from the screencap function is 854x480. Earlier I had tried a different media player, and I got about the same size, maybe a few pixels smaller. Any suggestions?
 
Do I need to buy the iTunes episodes to get any kind of decent quality, or should I just be trying to grab stuff from YouTube, or what?

Snipping tool?

@The_Mungoman  
What am I, a mohel?

 
Really now, use the Snipping Tool.

OK, all jokes aside, this is either something I’m not familiar with, something I know by a different name, or something I’ve forgotten. Please elaborate, kind sir/madam.

Click your Start icon in the lower left corner.  
Search for “Snipping Tool”.  
You should find a program with an icon of a pair of scissors.  
Use that to make screenshots.
 
If you’re using Windows 7, that is. If you’re using something else, I don’t know either.

Ah, that would explain my lack of familiarity. I’m still all the way back in the XP era…

@Elric of Melnipony  
Ah, the good old days :)
 
XP might have the Snipping Tool… You’ll just have to look for it.

A vertical resolution of 480 pixels is part of the NTSC SD standard, which is what you will get on American DVDs. If you’re looking for a higher resolution, you won’t get it - you can upscale the image, but that won’t add anything. If you want HD, buy the iTunes version or wait for a blu-ray release.
 
Also, upgrade your OS: Windows XP is no longer ed, except for commercial customers.

@nyxabuse  
I appreciate the info about resolutions, thank you.
 
As for the OS, that would require upgrading my hardware, which I can’t afford right now. :(

Well I don’t want to be That Guy, but have you considered letting Linux into your life? Xubuntu (for low-end machines) or Lubuntu (for really low-end machines) would almost certainly give you everything that you need (unless you need Adobe Premiere or something), and you’ll probably end up with your computer running faster than XP. You can even dual-boot & keep the Windows OS there for if you do need it for something.

It’s been suggested in the past, but I never really gave it much thought. Maybe I need to do some research…

This is usually accommodated in the media player. For example, in Media Player Classic, one simply navigates to File -> Save Image, and in VLC, one selects Video -> Take Snapshot. The only caveat is to ensure you are using a video renderer that is not a pixel overlay, which prevents screenshots. The options window can guide you through this.
 
You can also do Alt+PrintScrn, which limits the screenshot to just the window and makes cropping a bit easier.
 
On Windows, I strongly recommend either of those programs over a commercial solution or iTunes.

ON VLC, I have screengrabbing hotkeyed to the ‘S’ key, so I can take screenshots really easily.

@DragonRanger  
Yeah, the media player I’m using right now does that too. I was mostly frustrated at the small size of the image…

I ask the same.

@Elric of Melnipony  
You can get 1080p episodes and EQG stuff here https://yp1.yayponies.no/videos/episodes.php

At least the SMPlayer saves screencaps at the video’s actual resolution instead of the player’s resolution.