I sometimes need to edit image files, and usually I use GIMP (a really wonderful free editor).  However, as I don’t do this very often, I invariably right-click on the image and pick “edit”, forgetting that all that will do is launch the crusty old Microsoft Paint program   So, I did some web-digging this afternoon and came across a very simple article detailing the procedure.  Here’s a link to the original, and below is an excerpt for those of you who don’t need the video demonstration and so forth:

You need to go to the registry editor to make the changes. It is always a good idea to make a backup of your registry before continuing. Modifying the registry can be tricky if you don’t know what you are doing, and you can do major damage to your system if you aren’t careful

1. Press the start menu key and type “regedit” and locate the key:HKEY_CLASSES_ROOT\SystemFileAssociations\image\shell\edit\command
2. Locate the string value in the right windows called (default). The value will be“%systemroot%\system32\mspaint.exe” “%1″
3. Change the value to point to the program you want to use instead. E.g. “C:\Program Files\GIMP 2\bin\gimp-2.8.exe" “%1″ (This will set GIMP as default editor)

Don’t delete the “%1″ part at the end of the string. This is a variable that holds the name of the picture you are clicking on. You might also find that your path to the program might be different from mine.

If you want to set some other program as the default edit (or if your path is different), find it in C:\Program Files and when you have the correct “.exe” file in your sights, SHIFT-right-click and pick “Copy as path”.  That will put the full path and file name onto the clipboard so you can just paste it into RegEdit (above).