Web Quest Clare Steen Claire O’Sullivan James Costain
Vector and Bitmap images
Vector graphics are not
based on pixel patterns, but
instead use mathematical
formulas consisting of lines
and curves that make
shapes. With the exception
of Flash (vector graphics
program) most browsers do
not support vector graphics
On the web.
Bitmap (or raster) graphics are stored as a series of tiny dots called pixels. Each pixel is assigned a colour, and when they are viewed together, they form a picture.
GIF and JPEG
The Graphics Interchange Format is an independent image format that is suitable for transfer across slow connections. It is a compressed (lossless) format (it uses the LZW compression) and compresses at a ratio of between 3:1 and 5:1
It is an 8 bit format which means the maximum number of colours supported by the format is 256.
There are two GIF standards, 87a and 89a The 89a standard has additional features such as improved interlacing, the ability to define one colour to be transparent and the ability to store multiple images in one file to create a basic form of animation.
JPEG is a standardised image compression mechanism. JPEG is designed for compressing either full-colour (24 bit) or grey-scale digital images of "natural" (real-world) scenes.
It works well on photographs, naturalistic artwork, and similar material; not so well on lettering, simple cartoons, or black-and-white line drawings (files come out very large). JPEG handles only still images, but there is a related standard called MPEG for motion pictures.
JPEG is "lossy", meaning that the image you get out of decompression isn't quite identical to what you originally put in.
JPEG loses far less information than GIF.
Embedded Graphics and Linked Graphics
You can include information from another program or insert an entire document into your plan by linking or embedding it in Project as an object. The main difference between linking objects and embedding objects is the location of the data and how it is updated after you place it in the destination file.
A table of colour values used to reduce the data per pixel for encoding graphics images. For example a palette of 256 colours can be programmed to any set of 256 colours from, say, a total of 16 million and therefore each pixel is represented by only 8 bits.
Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. This can be contrasted to lossy data compression, which does not allow the exact original data to be reconstructed from the compressed data. Lossless data compression is used in many applications. For example, it is used in the popular ZIP file format and in the Unix tool gzip. It is also often used as a component within lossy data compression technologies. Lossless compression is used when it is important that the original and the decompressed data be identical, or when no assumption can be made on whether certain deviation is uncritical. Typical examples are executable programs and source code. Some image file formats, like PNG or GIF, use only lossless compression, while others like TIFF and MNG may use either lossless or lossy methods.
.bmp Format Files
The .bmp file format (sometimes also saved as .dib) is the standard for a Windows 3.0 or later DIB(device independent bitmap) file. It may use compression and is (by itself) not capable of storing animation.
Main disadvantage: loss of information, cross-platform incompatibility.
It is a web based resourse that can be used to upload images.