Size: the number of pixels horizontally by the number of pixels vertically. So there are two aspects of a picture you need to be aware of: But PowerPoint does take DPI into account as you’ll see later.

This is usually only applicable for printed media and defines how many pixels (dots) are crammed into each inch. In addition to the size of the picture in pixels, some image editors set a DPI (Dots Per Inch) parameter. This can cause pictures to appear blurry and degrade the quality of your slide show when displayed on a monitor or projector. When you resize pictures in PowerPoint beyond their original 100% size, extra pixels have to be ‘invented’ by PowerPoint through a process of interpolation. The first shows the image at a normal scale:īut when we zoom in you can clearly see each individual pixel that makes up the picture: The image below shows how pixels are used to form an image. Each of these dots is a single colour and the number of dots affects the file size of the picture. A raster or bitmap picture (contrary to a vector image) is made up of thousands of tiny dots or pixels.

OK, so this might not be the most exciting news headline but we need to start from the beginning.

So what do presentation professionals need to know about picture size and resolution? Pictures are made of dots But when it comes to PowerPoint, there’s an odd mix of measurements from the physical and digital worlds even though the majority of what is produced is shown on either a monitor or a projector. If you come from a web design environment you might be more familiar with pixels. If you come from a print media background you’ll be familiar with the importance of image resolution and how it affects quality.

Size of a powerpoint slide in inches