When you are leaving your photos in to be printed, you may choose the option Fill-in or Fit-in. Fill-In is the standard, default setting.
Most compact cameras and phones take photos in a 4:3 ratio. What this means is that if you select a 6×4 size print (a 3:2 ratio), the whole sheet will be filled, but this will result in parts of your image being cropped.
If cropping the image does not suit you, as you need the whole image printed, you may choose to print as Fit-In
Alternatively, if neither of these options suits you, you will need to crop your image to be a 6×4.
If any further explanation is required, Please do not hesitate to contact us.