SmillaEnlarger is a freeware program designed to let you magnify portions of an image. The software offers fine grained control over the expanded portion, including sharpness, dithering and the like, and it seems quite effective in improving the results. However no matter which way you cut it, the basic fact is if the information ain’t there, you’re not going to be able to improve it. Still it’s a nice little utility.
SmillaEnlarger is a small graphical tool ( based on Qt ) to resize, especially magnify bitmaps in high quality. ( The used algorithm is an invention of my own )