How many people have 4 gigabytes of memory ?

While most computers can display images taken from a digital camera, a special care is required to allow display of gigapixel images. Let’s see why.

Usually, a pixel takes 3 bytes of memory, one for each Red, Green and Blue component. Standard image viewers are loading the image completely in memory to display it, even if visible area of your image is only 1280x1024 pixels because of your physical screen size.

Best digital camera have a 12 Megapixel sensor, let’s say 4000x3000 pixels. This makes 36 000 000 bytes required for storing in memory the image. This is possible on any machine available now.

Let’s now take a gigapixel image at 40000x30000 pixels. This makes 100 times more memory, peaking at 3 600 000 000 bytes, that is 3.6 gigabytes.

Unless you have actually 4 Gigabytes of memory and your OS allows a chunk of this size to be allocated, then there is no way you can display the image on your machine, standard software will either crash or not allow image loading or will take forever to load.

Unless you use some clever way of organizing the image data and you have a dedicated viewer that knows how to handle this specific organization.

Next post will discuss this organization, usually called pyramidal tiling.