Make it smaller. What you are doing is squeezing the same number of pixels into a smaller area. Blur the image slightly in your paint program. The visual effect of increasing image size with no increase in resolution is seeing larger pixels. There are dozens of other formats, each with its own strengths and weaknesses.
Some programs even have their own formats designed specifically for use in their software.
For a more thorough understanding of these two formats see Adobe's feature The Right Match . It is a good introduction to graphics file formats, why different graphics formats are more or less suitable to certain tasks, conversion tips, and getting image files into your page layout program. Every one loves freebies and free GIF images are abundant on the Web. Although less plentiful, there are still some great collections of free clip art and photos in a variety of formats suitable for printing. In my recent searches I've found a lot of PCX, BMP, and WMF images.