Upsampling adds more pixels/dots per inch (dpi), but creates blurry images, ugly blocks of color, and high contrast in images. The only way resolution can be improved is by decreasing the image size, or by recapturing the image at a higher quality setting.
Postcrossing is an online project that allows its members to send and receive postcards from all over the world.
post / pÉÊst / n. a length of wood, metal, etc, fixed upright in the ground to serve as a support, marker, point of attachment, etc; either of two upright poles marking the beginning (starting post) and end (winning post) of a racecourse; the finish of a horse race; vb (transitive) (sometimes followed by up) to fasten or put up (a notice) in a public place