Raster images

Raster images

In computing, a raster image is an image that is created by the use of dots on a grid. Raster images are a collection of pixels that are used to make an image. The image below represents a raster image. The bits or pixels are on a grid that is used to make the image.

Compression’s

Files can be compressed to reduce the amount of space they take up. Compression usually involves reducing the quality of images. This is done by reducing the amount of pixels the image has. The lossy compression is what it is usually refereed to. There are some software that can reduce the file size of images greatly before the user starts to see the image degenerate. The lossy technique is mostly used to compress multimedia files.

The above image is an example of an image that has been compressed from left to right. As you can see the quality has been reduced. This would have been done to reduce the file size.

With lossless compression, every bit of data from the original picture is retained. Lossy compression permanently reduce the data of an image and the data is non-retrievable.

File extensions is a suffix to the name of a computer file. This is typically added on to the name of the file after a dot. File extensions are a type of metadata. They can be used to imply information about how the data in the file may be stored (encryption/locked). An example of the is txt. This file extension would look like ‘readme.txt’. This tells the user that is accessing the file that it is composed of a mostly small text that gives information about how to install a program for example.

BMP, This is also know as a bitmap image file. This file is used to store digital images just like rastor images. PNG also known as portable network graphics is a rastor image file that supports lossless data compression. This extension was originally created as a replacement for the GIF file extension. This is due to better quality and less data. (suffix name is .png).

TIFF or tag image file format is a common file format that is used for exchanging bitmap images across programs (suffix name is .tif). JPG is a type of file format that is used for photographic devices such as cameras. the suffix is .jpg or .jpeg. PSD ios the file extension name that is used for Adobe Photoshop documents. This file is used as it allows users to edit the different layers of the image and save it after wards.