I think you have to take about 10 months of classes from the nuns for that right? ok.. I know I'm not funny.... open your picture in a photo editing program like photoshop elements ($80.00) and then "save as" pic your flavor of picture file extension.....your done.
You need a graphics program/software. I use Paint Shop Pro, its' cheap and it's fairly intuitive. You can change a pic from virtually any format to any other format AND you can easily resize a pic based on percentage of original size, physical size, or number of pixels. With a single button you can also improve the quality of a dark picture and/or remove speckles, etc. PhotoShop has good products as 30roadster suggests, take a look at all of them and decide which one works best for you and your budget.
I do that stuff for living so if it's just a one off thing pm me and I can help you out. (No charge of course)
The Jalopy Journal
