It seems that many people have no idea how to perform the most basic tasks on a computer so this mini-tutorial explains how to reduce an image size for uploading to a forum or web site. It’s also handy if you want to send the image to a friend because sending a full-size image straight from your camera is likely to LOSE friends if they have a "data cap" limit. As I’m not familiar with Windows Operating Systems, I hope that someone else will post a tutorial for those.
Apple Macs using "Leopard" 10.5 or later OS.
Right-click on the image icon and open the image in "Preview".
In the menu bar, click on "Tools" then select "Adjust Size".
Set the "Resolution:" to 72 pixels/inch.
Set the "Width:" as desired, for example 450 pixels.
Hold the [alt] key while you click "File" and select "Save As..".
Rename* the file and select the location where you want to save the new small file.
*I simply add -s to the filename to indicate that it’s my small version.
This may look complicated but it’s very simple in practice.
You now have a small image file that can be uploaded very quickly without using excessive bandwidth. Perfect for "Facebook" and forums.
Note that "Preview" offers additional facilities for cropping and correcting contrast etc.