If you are a regular user of Twitter, you will know of those awkward situations when you post a message like, “Aww, I’m currently looking at the picture of the cutest kitteh,” and the only reply you get is “Yeah? Prove it!”

You need to have a way to show the world what you are doing on your computer, whether it is to prove that you really are wiling away time as you claim to be, or to take shots of an application misbehaving so a friend can help you out with it. Now that we think about it, you might just be a student who has to show an image of a software in a report. In any case, you need one of these software.

What follow are five awesome tools that can take screenshots, and also happen to be totally free. Truth be told, Windows is already capable of taking screenshots. Far in the top-right reaches of the keyboard are three buttons, their purposes lost in the mists of time. Among them is the mighty ‘Print Screen’ key, usually helpfully labeled as “Prt Scr Sys Rq”.

You will need to familiarize yourself with this key for any screenshot application. What — you might ask — do these screenshot applications do then if this much is possible directly with Windows? Much more — is all we can say.

1. Lightscreen

If you are looking for simplicity, you can probably stop right here; Lightscreen makes the basic task of taking screenshots dead simple. If all you want is to automatically save a shot of your screen when you press a button, this software is enough.

That isn’t to say this software has no features at all. Other than taking a shot of the entire screen, it can also take a shot of the currently active window, or any area on the screen. While selecting an area on the screen, it can also zoom into the surrounding areas so you can get pixel-precise shots. You can have it ask for where to save your screenshot when you press the screenshot button, or pick a folder and name to save with automatically. You also can opt to remove your mouse cursor from screenshots.

Lightscreen is not only free, it’s open source, so some geek somewhere can already start adding new features while you download it. Lightscreen can also be installed to a pen drive, so you can take it anywhere you go.

2. Greenshot

We’re not sure how environment friendly Greenshot is, but it’s a pretty awesome screenshot software nonetheless.

Other than the zoom on capturing areas feature of Lightscreen, it offers pretty much all the features, and more. Taking screenshots is as simple, but you have more control over where the screenshots go. On capturing a screenshot but pressing the hotkey, you can have your image copied to the clipboard, saved to your hard disk, emailed, opened in an image editor, or even sent to a printer like the good old days — when people had printers. If you choose to save screenshots, they will automatically have the title and time of the screenshot in the file name. You can even pick multiple of these options; so a screenshot can be copied to the clipboard, printed, saved and also edited with the press of one button.

There are two areas where Greenshot offers much more than Lightscreen, the first is that it lets you select which window to take a snap of by selecting it, and the second is its inbuilt image editor.

The inbuilt editor lets you edit the image right after capturing it, so you can remove the mouse cursor, crop the image, blur parts of the image you don’t want others to see, highlight the ones you want them to focus on and draw shapes and add text.

Like Lightscreen, Greenshot too is open source, but no portable version is available.

3. Jing

Jing is the simplified version of TechSmith’s SnagIt screenshot tool designed for the casual screenshot taker; i.e., someone who does not need to take a few screenshots every minute.

Some of the main differentiating features it offers, in comparison to the software mentioned above, are video capture support, and online integration.

What webcams do for sharing what’s going on outside your computer, Jing does for what’s happening inside your computer. It can record a video of whatever is happening on screen so you can share it with others.

It also integrates with the Screencast.com web service offered by the creators of the software; which allows easy storage and sharing of screenshots.

Both the software and service are available for free, but also offer more functional paid versions.

4. Screenpresso

Of all the software we have talked about till now, Screenpresso has the most features. If you need to capture and manage many screenshots, Screenpresso is what you might use.

One of the interesting features it offers, that none of the above have is the ability to capture proper window borders in Windows Vista and Windows 7. Instead of capturing the blurry remains of what you can see behind a captured window, it can clean out the title bars.

Want to capture a window that has a lot of content accessible only by scrolling the contents? Screenpresso can do that. Want to share stuff with multiple services, YouTube, Twitter, Flickr, Dropbox, etc., you can do that as well.

Screenpresso too has a paid version that unlocks some of the features such as high quality video recording and much more.

5. ZScreen

ZScreen is the mother of all screenshot applications. It’s so bursting with features that we dare not mention all — not much point anyway, but the time you finish reading this, a few more would probably have been added. Lets instead mention one major feature that the previous two software have had but it doesn’t – video recording.

You can get lost in the number of options it supports. In fact, it supports so many online services for uploading that it actually offers a separate software called ZUploader just for that purpose.

So if one of the above software suffices for your needs, we’d say go for it. If you still feel like you are missing some functionality, check out ZScreen. It is once again totally free and open source, so you can ask your grandma to add features if there are still some missing.

Your favorite tool isn’t listed? Mention it in the comments! You’re abandoning you current tool to pick one of these? The world needs to know, comment below.

Image by Phil Sexton via Flickr (cc)