In researching images for a recent presentation I discovered this great website – Flag Icons.
Every country looks to be represented. But the part I used was the “web 2.0” design styles for each. Just find the country you need a flag for and then select the flag style that works best with the presentation.
In addition there are options for saving as a .jpg (white background) or .png (transparent background) and sized from 50-800px wide.
– Troy @ TLC