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#Binary smallimage software#
#Binary smallimage code#

The effect of zooming in on a high and a low-resolution bitmap image What is resolution and how does it effect the size of an image file? 111111111111111100000000 in binary (note the use of 24 bits)ĮXPANSION TOPIC – Colour mapping and Direct colour.

#Binary smallimage code#

For example, if 24-bit direct colour was used then the code for a yellow pixel (maximum red and green and zero blue) would be In this the bits allocated to each pixel separately encode the relative proportions of Red, Green and Blue to specify what is called an RGB colour. In higher colour depths (8 bit and above) a system called direct colour is used instead. Each of the 256 colours in the palette is indexed using 8 bits so it is the 8 bit index value that is actually stored for each pixel in a GIF file.ĭirect colour – As the colour depth increases, colour mapping and palettes become impractical due to the number of possible colours that the image can display. This table stores each of the 256 colours using 24-bit direct colour giving 16,777,216 possible colours. However, every GIF image can have a different set of 256 colours because they are stored as part of the file in a palette table. Palette tables – The GIF file format uses 8 bits for each pixel so each pixel can display 256 different colours. This is called colour mapping and an example might be the binary code 110 representing yellow. Colour mapping, palette tables and Direct colourĬolour mapping – With low colour depths (up to 8-bit) it is practical to map every colour to a binary code because there are not too many colours involved. SUMMARY: The greater the colour depth of a bitmap image, the greater the file size because more memory is used to store the colour data about each pixel. With 3 bit colour depth the number of bits used to store the information about each pixel is 3. What is colour depth and how does it effect the size of an image file? Colour

#Binary smallimage software#

NOTE: An image file may also contain metadata describing the type and amount of compression in the image, the software used to create the file and if it is a digital photograph, the date and time the image was taken and the camera/lens settings. The same data but the WRONG colour depth metadata – 2 bit colour depthĪn image with the CORRECT size metadata – 16 x 24 pixels

The colour depth – so the correct number of bits are used to represent the colour of each pixel.Īn image with the CORRECT colour depth metadata – 1 bit colour depth.

The resolution – so the image displays at the correct size.

The height and width of the image – so each line of the image starts in the correct place.

Metadata is needed in a bitmap image file because the software that displays an image needs to know: Why does metadata need to be included in an image file?Ī typical example of the metadata stored in a digital image Also, if a vector image was scaled-up and then saved it would have the same file size as the original. The result is that the file size of a vector image would be considerably smaller than the equivalent bitmap image which would need to store the colour information for every pixel.Īlthough vector images can have graduated fills these are mathematically defined and cannot represent the level of detail needed for photographic images.Īs well as the smaller file sizes, vector images have the advantage that they can be scaled to any size without the loss of detail that would occur with a bitmap image. This information would be stored using binary codes for the instructions. For example, to save a vector image of a circle the software only needs to store: Vector images store information as mathematical instructions rather than as individual pixels. Vector and bitmap images compared, showing the effect of magnification on each