First of all I wish to rant about the “via MSN”… this seems slightly stupid to me, when anyone who would be answering this is a mac user therefore iChat seems a better choice, but anyway… moving on

Ok I am 95% sure that you can not change screenshots taken using command shift 3/4 saving to desktop… so I can only offer alternatives

You could always use Apple Grab, but I feel it to be fairly limited, although you can save to a pre-definated folder. But I would recommend either of the two options listed below….

Screenshot Plus is a simple and very easy to use widget that allows you to take screenshots and save to a pre-defined folder easily.
A more professionally method is that offered by use of Snapz Pro X which is very handy… requires you to *cough* pay *cough* $29, but do not worry, for I can help you out there. Message me if you think wish to know further details.

Oooh, you are a gem!
Seeing as how I’m trying to cut down on the use of software of dubious provenance, I went for the Screenshot Plus option.
Works nicely as far as I can see - does exactly what it says on the tin.

My one drawback is that I have to go to dashboard to use it. Now, I like dashboard, very useful, but it is rather a draw on the old CPU (old being the operative term here). My ideal would still be to force the cmd+shift+4/3 option to save to the desktop, but failing that this is a great alternative
It’s definitely time for me to zap the harddrive and install 10.4 properly instead of over the top. *sigh* Anyone know where I can get a bargain on an external harddrive?

And in my defence, when I say “msn” I mean some form of instant messaging. In my case, I use Adium. Technically, it’s still MSN because Adium piggybacks on their servers, but I don’t have to use the crappy (and horrendously unstable) Mac version of the MSN client. And I can be signed into Yahoo! at the same time.

Don’t get me started on why Yahoo! - suffice it to say, webcams do NOT play nicely when you’re doing things cross-platform.

I also use Adium for msn, and then iChat for my .mac and googletalk accounts.
Sorry I couldn’t help you with exactly what you wanted, but Screenshot Plus is handy enough. I use a MightyMouse, which is just because my Apple wireless mouse is is a one button mouse, which is to irritating. But as I was saying, I use a MightyMouse and so when I click the middle button it opens dashboard, so it isn’t really that much effort. Also, my iMac 2.1GHz/ 2GB ram copes. I will do some more research though and see if there are any other options.

I’m sure there’s a way to edit the prefs for this, but so far all I’ve found is how to change the default format, not the default location. I’ll figure it out someday.

I have the utmost faith in you sweetie

As I said…. I don’t think it can be done. I spent like 30 minutes attempting, a further hour researching… both leading to the conclusion that I don’t think it can be done.
If I am wrong, please forgive me… I must have been having an off day… usually smart

I have to say Crazy, my own researches have led me more towards your “it can’t be done” side of the argument than Surly’s “it can if I could just remember how”.

Then again, the Surly One has mysterious uber-godlike powers when it comes to messing around with the inner workings of Macs, so I’m gonna give him the benefit of the doubt for now.

Till that distant “someday” however, I’m using the Screenshot Plus widget and am liking it

It may be a long time ago, but I have yet another method…, maybe more what you were originally looking for. It was the OS X tip of the week… but in case you missed it :

Well we all know command-shift-3 (or 4) takes the screenshot and saves it to the desktop, well Control-command-shift-3 (or 4) saves the screenshot to the clipboard and then you can go and paste it were you want it.

Ok, I might be being blonde here, but once I’ve got something on the clipboard, how do I get it OFF the clipboard and into the folder?

Nobody taught me the Mac way to do things - I’ve been picking it up as I go along - and clearly even after three years I have a fair bit to learn
Also, that shortcut is a bit of a handful. I can get three keys at once, but four seems… excessive. The widget is still the favourite solution at the moment (mainly because it remembers how much it’s done and saves sequentially to the folder without me telling it too).