Both Epson's PictureMate Charm PM 225 Compact Photo Printer and HP's Photosmart A646 Compact Photo Printer cost roughly the same, but which would better suit your needs? One printer has high quality photos but few options; the other printer's quality is not as quite good but it lets you print more sizes of photos and has other interesting features. Melissa Riofrio, PC World's printer expert, explains the differences.