Unit 30 D2

Compression.

compression is reducing the size of a larger file so it will not lose its quality, file compression is usually determined by 5 options
low
medium
high
very high
maximum
compression is mainly used for images that are being uploaded to web making the time it would take load reduce. file formats are all saved differently and the best file format for compressing would either GIF or JPEG. JPEG is the more popular choice as this type of image can be kept relatively small without it losing quality.

Color Depth

Color depth is the amount of bits used to represent different colors, meaning that the higher number of bits the better the quality of the image. for example a 24 bit image is going to be a much better quality than an 8 bit image. also color depth can be a problem when printing as some printers can only print a certain color depth. color depth can also be a problem when saving an image as file types such as GIF as they have a very limited color pallet.

Resolution

Resolution is the quality in an image which is normally measured by pixels or dots, the measurements are called pixels per inch or dots per inch. PPI is used for on screen resolution where as DPI is used for printing.

the higher the. web graphics are normally 72 PPI  meaning 72 pixels for every inch.the higher PPI the better the quality and the lower the PPI the lower the quality, this is because there are more pixel per inch however having said this vector images do not have this problem as they have no resolution due to the fact that they are not made up of individual pixels instead they are made of different mathematical equations.