Image Resolution

When you format a picture in InDesign, a good rule of thumb for the image size in pixels in the length in millimetres times 5, if it is a rough print from a laser printer/home printer. That means the size for the picture should be 5 pixels/millimetre. However, if you were doing an image for a glossier magazine, you would need to times the length by 12, as the image would have to be of higher quality. If, for example, I needed a picture to be printed on a laser printer whose size was 80mm wide, it would need to be 200px. However, if the same picture was going in a glossier magazine, then it would need to be 960px wide.