I was (and still am) a big fan of Microsoft Photo Editor, which is a handy litle application that ships with Microsoft Office 2000. It enables you to do rudimentary editing of graphics files. It also lets you save a file originally in one format into a different format, so you can convert a JPEG into a GIF, for example, really easily.
Along came Office 2003 and this version of the office suite included a product called Microsoft Picture Manager, which was the replacement for Photo Editor. This new, improved, application does not include the simple transformation functionality between JPEG, BMP, PNG and GIF that Photo Editor offered so effortlessly. Also, to my mind at least, it is a much less straightforward application to use. I have never liked it.
On my own laptop I have the history of having instled Office 2000 and then Office 2003 (yes, dear reader, that side-by-side migration is not without its gotchas, but that is another story) and despite technical posts out there that tell you that Office 2003 uninstals Photo Editor, I have somehow managed to keep it installed. Can't remember how. But at work they gave me a brand spanking new box to work on (well, the hardware was new; thankfully it still had XP rather than Vista [bleh] or Wndows 7 [jury still out]), which had Office 2003 as a clean instal. Of course I I found myself needing to knock up an image as a JPEG and for some reason all I had was its GIF equivalent. So havinig fought with Picture Manager and conceded defeat, I searched online and found this:-
Cool Utils - Free Online Image Converter
It does what it says on the tin - i.e. it converts an image file from one popular format to another. This is really handy if you find you do not have the necessay tools on the workstation that you are using.
There appear to be a bunch of other utilities on that web site. I cannot speak about them as I have not checked them out, but this one simple - and free - utility saved me a bunch of effort, so I am happy to pass it on.