File Formats (P2)

File management

Naming files:

It is important to keep the name of files short, this makes it quick and easy to search and find images. When naming an image file you should pick a meaningful name to do with the image for example an image of a red door could be called “red_door” or “door_red”. This method makes it easy for anyone to know what the file will contain. Another good way to name image file is to stick to naming conventions such as using a _ instead of a space in the file name.

Using naming conversions and meaningful names improves the organisation of files and make it considerably easier to find image files.

Folder structures:

Folder structures are an important part of maintaining organisations with files. Most operating systems allow multiple folders to be created and then subfolder within that folder, this allows for a complex but organised file layout. This method of origination allows you to place image files into groups based on what the images have in common. An example of this would be placing all the pictures of laptops in one folder and in another folder all the pictures of Xbox 360.

Moving files:

Moving files can be risky if certain precautions are not taken to ensure that multiple copies of files are made, if these precautions are not taken you run the risk of losing a file permanently.

Creating copies of an image file and moving to storage device such as a USB stick is a good idea due to how easy it is to copy and move files on the latest operating systems. One of the easiest and most common ways of moving and copying files at the same time is to copy and paste the file into the desired location.

Deleting files:

Deleting files is an easy and basic operation on most operating systems, but care should be taken when deleting files as hard drives do have a data recovery system allowing files to be restored.

Vector and Raster Graphics:

Raster (bitmap):

Raster images are made of pixels of a set colour and shades that create the image. Each raster image pixels represents a different colour rather than an instruction, this is one of the main reasons raster images are used in high detailed images or photographs. This file type does not scale very well; this is because you are spreading the same image data over a larger area. The image on the right is an example of how a raster reacts to being scaled in comparison to a vector image.

GIF:

Graphics interchange format is a form of raster graphic. This file format supports animation and transparency making it very popular on the internet; this is also due to its quick loading times. GIF files support images up to 256 colours; this limitation causes GIF’s to have a poorer a quality in comparison to other file formats.

 

Vector:

Vector images use a set of instruction to create an image. This allows vector images to be scaled up and down without the losing any of the image quality, this makes vector graphics the ideal file format for a logo because it may need to  be produced at multiple sizes. A major disadvantage of this file format is its inability to handle complex graphics such as a photo that could contain a large amount of different instructions. The image on the right is an example of how a vector image cannot give the same graphical quality of a photograph as a raster image.

SVG:

Sizable vector graphics is a vector file format. This file format is an all-purpose vector format. As with the majority of vector graphics it cannot display photorealistic images very well .This file format supports animation and transparency. It is commonly used on interactive web pages and is also supported by the majority of modern browsers.

 

Lossy and Lossless Compression:

It is possible to reduce the file size of an image using compression. The first method of compression is called lossy compression. Lossy compression works by putting the colour information into blocks and eliminating unnecessary bits of information, this in turn dramatically reduces the file size. Once an image has been compressed you cannot get the original uncompressed file back

The second method of file compression is lossless.  This method allows the image to keep all of its uncompressed data. It does this by using data algorithms; these algorithms break the image data down for compression but also allow all of the data to be fully restored.