Hi FenderBean
In order to resize images without loosing resolution of the image one would have to convert the image to vector format as raster images (jpg/bmp/tif etc) start to loose resolution if enlarged by a multiple of times. For this reason Coreldraw and Photoshop and Illustrator can be used to convert images. If you are subscribed to Jetpower magazine there were a number of articles covering this topic. Here is an example of the Greek Corsair which i am sure you know. The pirate image has been enlarged and then converted to vector format. The latter can be enlarged to any size without any loss in resolution.
Hope this helps.

Reuben