This page will give you some examples to work with. The same blue square will be displayed in different sizes, with the size displayed above it in pixles (px). This should hopefully give you a good idea of how big you'd like your image to be when you're resizing it.

10px by 10px
square
25px by 25px
square
50px by 50px
square
75px by 75px
square
100px by 100px
square
150px by 150px
square
200px by 200px
square
250px by 250px
square
300px by 300px
square
400px by 400px
square
500px by 500px
square

At standard quality (72 pixels per inch) a 6" by 4" picture (standard printed photo size) would look like this:
432px by 288px
square
Last modified: Monday, 6 August 2012, 2:09 PM