I need to find out how i can change the aspect ratio of photos now at 4:3 to a ratio of 16:9 which is for a di?

which is for a digital photo frame that I received as a gift.I need to find out how i can change the aspect ratio of photos now at 4:3 to a ratio of 16:9 which is for a di?Most photo editing programs will allow you to resize your photos. Assuming your present photos are 800x600 pixels (4:3) resize them to 800x450 pixels (16:9).

Irfanview has this feature and it's easy to use, just uncheck the Preserve Aspect Ratio before resizing - http://www.irfanview.com/