A file format is a standard way in which information is encoded for storage in a computer file and consist of bits that comprise of the image and header information on how to read and interpret the file. A list of the most common file formats can be found below:
JPEG – short for ’Joint Photographic Experts Group’ (the committee that created the file type). The JPEG is an image file that is a popular way to compress and store images for use on a web site page. When JPG files are saved, they use “lossy” compression, meaning image quality is lost as file size decreases.
PDF – Documents are saved in PDF (portable document file) format when it is likely that users will want to print information without the need to alter the document. Documents often take the form of printed books or leaflets and are provided on a website so you can get immediate access to the information. A PDF can either be read in your browser or downloaded to your computer and viewed offline. Adobe Reader is needed to read a PDF file.
GIF – Graphics Interchange Format (GIF) contain less colours than a JPEG which means they are much quicker to decode so they are more commonly associated with websites and emails where speed is important. Banners, simple images, and computer graphics often contain fewer than 256 colours, so the greater speed gives the GIF format the advantage.
TIFF – A Tagged Image File Format (TIFF) is an uncompressed, high-quality format that is popular if maintaining the image’s original quality is important. TIFF file formats are used for storing very large, high quality images and are the favored image format in many graphic applications. Due to the lack of compression, Tiff files take up more memory space and can take longer to write to.
PNG – Portable Network Graphics (PNG) is an image format that uses lossless data compression (allows the exact original data to be reconstructed from the compressed data without losing quality). PNG was created to improve upon and replace GIF as an image-file format not requiring a patent license.
Raw – this is a format in digital SLR cameras which prevents any in-camera processing affecting the data and quality of the photograph. The Raw format gives all the information captured by the camera. Raw images are the best quality you can get but due to all the information they take up more space and take longer to process. Professional photographers usually shoot Raw photos as they allow more flexibility when it comes to digitally manipulating an image.
PSD – PSD is Photoshop’s own file format. Photoshop documents are created when you separate your image into layers using the software. PSD files are able to support any changes you make to an image and when you compress the PSD file it would usually be into a Jpeg format.
SVG (Scalable Vector Graphics) – this format of image construction uses XML to describe two-dimensional vector graphics.