I like to set the width of "wide" pictures to 500 pixels.  I set the height of "tall" pictures to 700 - this comfortably maximizes the size of the pic for a 600 x 800 display.

Then the image needs to be compressed in order to ensure that it renders promptly, and is efficiently stored on the web server.  Here's how:

====== iPhoto ======
For all you mac users out there, you can simply select the photo(s) you want to use, and then click ''Share''->''Export''.  Enter a width value of 500, and follow the instructions to finish exporting.

====== Adobe Photoshop ======
  * Open the image and rotate it as necessary
  * Resize the image
    * Click ''Image''->''Image Size...''
    * Enter a width of 500 pixels, the height should change automatically.
    * Click ''OK''
  * Save for Web
    * ''File''->''Save for web...''
    * Choose ''JPEG'' and ''Maximum'' from the dropdown options.
    * Click ''OK'' and save the new image in a place where you can easily retrieve it for uploading.



====== GNU Image Manipulation Program ======
If you can't get your hands on a copy of photoshop, this software can stand-in for most uses and it's free...
[[http://gimp-win.sourceforge.net/stable.html]]
  * Open the image and rotate it as necessary
  * Resize the Image
    * ''Image''->''Scale Image...''
    * Enter a width of 500 pixels
    * Click ''Scale'', the height should change automatically.
  * Save the Image
    * ''File''->''Save As''...
    * Rename the file appropriately
    * Expand ''Select File Type (By Extension)''
    * Select ''JPEG image''
    * Click ''Save''
    * Check the box ''Show Preview in image window''
    * Move the slider to the desired quality (I like 95 or better)
    * Click ''OK''

====== Irfanview ======
Here's another one that should be pretty simple to setup and it's free to download and use. I have not tried resizing/optimizing for the web with this one but it should be pretty easy. Directions forthcoming...
[[http://www.irfanview.com/]]