Originally Posted by The_Other_One

We need some more information... Technically any printer can print at 4x6. There are specific printers that only print on 4x6 paper, but I normally just print multiple photos on one sheet and cut them out.

I don't know what program you use, but a BIG factor in the print quality is the DPI. I always make new images at 300dpi and paste the picture into the image. I then tweak/free transform it so it fits correctly. Doing it this way almost always results in a much higher quality print than say using a more standard 72dpi template.