More on images

This page presents some advice regarding images.

Image type

Obviously, the existing images already have a type. But when you create an image using graphics software, you need to decide which type you are going to save it to.

JPG vs PNG

You will often save an image as bitmaps, that is either in the JPG or PNG file format. Since file size can be an important consideration, it is good to know that, for the same image quality, the file size depends on the "content" of the photo. Indeed, if the image is a photo, therefore containing a multitude of colors and shades of colors, it is better to save it in JPG format. On the other hand, if the image is a drawing, containing a limited number of colors, it is better to save it in PNG format.

If you are unsure, save the image in both JPG and PNG formats. Make sure the image quality is adequate and choose the image file that has the smallest size. You will invariably find that the JPG file of a photo has a smaller size than the PNG file, and that the PNG file of a drawing has a smaller size than the JPG file.

An advantage of the PNG format that should be mentionned is that it supports transparent color, which makes it possible to have a transparent background, which is not possible with the JPG format.

You will find further information on the web about when to use either format, for example here.

Image size

The dimensions, width and height, of images are measured in pixels which translate to mm (or inches) depending on the size and setting of your screen.