Bitmaps are grids of thousands of pixels of certain colours to make up an image. Bitmaps take up more data as the computer needs to save each and every pixel in the whole image, due to all of the pixels a bitmap image will take longer to send to someone as it needs more packets to be sent. An example of a bitmap graphic is a photograph. The more colours that can be saved in a bitmap graphic, the better and more smooth the image will look. This is called colour depth. For example, a jpeg has 3 bytes (24 bits) which means that it can save up to 16.7 million different colours and this is called “true colour”. While a jpeg has a colour depth of 3 bytes, a gif only has a colour depth of 1 byte which means that it can only hold 256 colours which and so should be used for animation or simple pictures. When an image doesn’t look very smooth or clear that means it is pixelated which can also be called “posterized”. Images are more likely to be posterized if they have a small colour depth such as 1 byte. A megapixel is 1000 pixels. The resolution is the number of pixels and quality on a monitor and is measured by the number of pixels that there are horizontally multiplied by the number of pixels that there are vertically. The dimensions of a bitmap image are the width and the height and multiplying these together then gives you the resolution. The dimensions of an image are the number of pixels down the side and the number of pixels along the top or bottom. The metadata of an image is data you don’t know is there such as the location that the image was taken being saved. The DPI of an image is how many dots per inch there are. The higher the DPI the better and more clear the image will be, although the higher the DPI the longer the image will take to print, load, send, save etc. So, it is a good idea to get a good balance of high DPI and low DPI (medium DPI) so that the image still looks quite good but also doesn’t take long to send, load, save, print etc. The image resolution of an image is a measure of the image quality. The number of pixels that an image contains is the width (pixels along the bottom or top) multiplied by the height (number of pixels down the side).