Instructions using XP and your free Paint program. If you're using Windows 7 it'll be a LITTLE different. I also prefer www.imgur.com
to any other for uploading photos. No need to register or sign in or any other silly stuff.Do this
(if you're using Windows):
1) Open Paint (it's in "Accessories")
2) Browse to your image
3) Open image
4) Now click on "Image" in the Paint tool bar
5) You'll get a drop down menu. Now click on "Attributes"
6) You'll now see the image size in pixels. If taken with a camera, it'll be HUGE. You'll want the image no larger than 400 to 500 pixels wide. "Make it so." Make sure you keep the ratio between width & height or it'll be distorted.
7) If you're happy with the size for posting or emailing, click "Save As" and give it a NEW Name--otherwise you'll lose the large picture.
I usually go with "pic-sm.jpg" (for "small")