JPEG (JOINT PHOTOGRAPHIC EXPERTS GROUP)Mainly used on the web, principally to reduce size of image and lessen download time. It uses compressionto reduce file sizes, which leads to the loss of some of original data. It supports full colour. Capable ofshowing images containing over 16 million colours.
GIF (GRAPHICS INTERCHANGE FORMAT)Mainly used on web for images with sharp content such as logos, screenshots and basic animations. Capableof showing images containing 256 colours so it is not suitable for photographs.PNG (PORTABLE NETWORK GRAPHIC)Created as a replacement for GIF on the web. It produces smaller file sizes than GIF images but is capable ofshowing images containing over 16 million colours.COMPRESSIONFile compression is used to reduce the size of a file. There are 2 main reasons forfile compression:? Less storage space is required for the compressed file.? The compressed file can be uploaded or downloaded quicker from theInternetN4/527Strathaven AcademyGRAPHIC RESOLUTIONThe resolution is the size of the pixels and is usually measured in dots per inch (dpi). High-resolution graphicshas a large number of small pixels.
Low-resolution graphics has a small number of large pixels.Below is an illustration of how the same image might appear at different pixel resolutions.COLOUR DEPTHThe number of bits that are used to code the colour of each pixel is calledthe bit depth. An image with only 1 bit depth will only represent 2 colours(21) – Black and White.
An image with 24 bit depth will be able torepresent 16777216 colours (224).1 bit: 2 colours 2 bits: 4 colours 4 bits: 16 colours 8 bits: 256 colours 24 bits: 16777216coloursThe pictures below show you how the same graphic would be represented depending on the bit depth andhow the greater the bit depth, the higher the quality:FILE SIZEAs you might imagine if you increase the resolution and the colour depth of aN4/528Strathaven Academygraphic you increase the file size.N4/529Strathaven AcademyFile Format Colour Palette Used ForJPG Millions of colours ? Still images? PhotographyGIF Max 256 colours ? Simple animations? Graphics with flatcolour? Graphics withoutgradientsPNG Unlimited colours ? Still images? TransparentJPG, GIF AND PNG DIFFERENCESDATA PROTECTION ACTThe Data Protection Act was passed by Parliament to control the wayinformation is handled and to give legal rights to people who haveinformation stored about them.DATA SUBJECTThe people the company is holding the information about for examplepupils in your school or books in the school library.The data subject has certain rights. They have a right to? Be informed that their data is being processed/used? See a copy of their own data? Have any errors in the data correctedTHE EIGHT PRINCIPLES OF DATA PROTECTION1. It must be collected and used fairly and inside the law.
2. It must only be held and used for the reasons given.3. It can only be used for those registered purposes and only be disclosed to those people mentionedin the register entry.
4. The information held must be adequate, relevant and not excessive when compared with thepurpose stated in the register.5. It must be accurate and be kept up to date.6. It must not be kept longer than is necessary for the registered purpose.7. The information must be kept safe and secure.
8. The files may not be transferred outside of the European Economic Area.N4/530Strathaven AcademyCOPYRIGHT, DESIGNS AND PATENTS ACT(PLAGIARISM)With the increasing use of computers, material can be copied veryeasily. Increasing use of the Internet for downloading music can leadto copyright infringement.Downloading music or movies without paying for them would breakthis act.Copying text or images from web pages and using them on yourown web page would break this act. (Permission would need to be sought).
Software piracy is also covered under this act. Software piracy is when you use software you do not have alicense for.