See Dick and Jane Capture and Post a Screen Image to the Forum: an image posting primer!
To 'capture' application screens, you click on them so they are the 'active window', then hit the <ALT><Prt Scr> combination (anther handy one is <CTRL><Prt Scr> - captures the whole desktop image...), which puts the screen image onto the clipboard; then, open Paint (or any other graphics program you're familiar with) and either do Edit/Paste, or a <CTRL><V>, to paste the image; save it with a File/SaveAs with the Jpeg file type selected (.JPG), and you'll be ready to post it.
To post the images, the first thing you want to do is go to ImageShack: http://imageshack.us/
and create an account (it's FREE) for yourself (and save a bookmark - I use it so often, that I keep the shortcut to it on my desktop - but then I've got a lot of desktop [four monitors worth - ]); there are any number of these file and picture 'sharing' services (I use MediaFire for sharing files like BIOS and drivers here...), but ImageShack seems to have a minimum of intrusive crappola, and seems to dependably 'keep' your files; if you want to use a different one, this should give you a pretty good general idea of 'what to do'...
Once you're registered, going to the site will 'pop' this screen:
Click on the 'Browse...' button, and find your image file; once you've selected it, a click on the orange outlined 'start upload!' button will get it up there, and it will go to this screen:
Click in the window labelled 'Hotlink for forums (1)' (encirled in green in the illustration...), and copy & paste it to your post - it will look like this:
where you simply paste on top of the 'undefined', and click OK. To use this method, however, requires that you enable 'scripted controls' in IE:
Click your way 'in' to InternetExplorer - Tools-> InternetOptions-> 'Security tab':
Click on 'Custom Level':
scroll down to "Allow websites to prompt for information using scripted windows", and click 'Enable' - then 'OK' and save the settings... A little more difficult, but a little more elegant
If you leave a space between the brackts it won't post either.
So which of the hosting sites will allow you to upload with ftp? I always use my RoadRunner webspace for stuff, you can reserve space for each email alias you have, thereby getting tons of space. They have two free types of webspace, one with 5MBs I think, the other with 10. The 5MBs is easier to use.
Note the .th. at the end of yours. You got the url from the thumbnail (th) of the image but I got it from the full-size image. Just need to copy the right image location.
See on the lower right-hand side of you image page, it shows both Image URLs and Thumbnail URLs.