D2: Discuss the impact that file format, compression techniques, image
resolution and colour depth have on file size and image quality.
Introduction
In this report I will be discussing different features of file formats that can help reduce
the size of these through different compression methods such as Lossless and
Lossy. I will then go on to talk about the impact of colour depth, image resolution and
quality for an image. However first I will pick two file formats such as JPEG and PNG
state the features and then compare them both on different levels.
File format: JPEG vs PNG
What’s a JPEG?
JPEG Is a file format that is normally used for Photographs however it can also be
used for other things. This type of format is normally a compressed image file (lossy)
however the how much the file is compressed can be altered to still obtain good
image results but a lower file size. Furthermore it is not normally limited in the
amount of colours it can support which is 16.7 million colours hence why it’s normally
used in Photographs and also most software programs support it as it is a file
extension that is used worldwide as a standard. JPEG is normally represented by the
file extension .jpeg.
What’s a PNG?
PNG File format was introduced in 1994 and is normally used in Icons because it
supports transparent/ alpha channel images which means the background will not
show. It is not used in Photographs too much because of the compression method
which usually outputs the image at a lower quality. PNG has lossless compression
which will reduce the original file size to make it smaller so sometimes you will notice
that some of the file sizes are quite small normally under Kilobytes however with this
the quality of the image will get reduced drastically so if you zoomed into the image
you will see many pixels. The good thing about PNG is it supports 24 and 32 bit RGB
colour pallet which is similar to JPG so again around 16.7 million colours and also
grayscale images. PNG is normally represented by the file extension .png.
Main differences
The main difference between the two image file formats is the type of compression
that is taken place. JPG which uses Lossy Compression which is useful as it helps
remove unimportant data which has not effect on the images representation however
if you did decided to zoom into the image it will look pixelated and blurry. PNG on the
other hand supports Lossless compression which makes sure the image is not
missing a single bit of data so when the image is represented although you might not
see any effect when you zoom in it will not look as pixelated as the JPG Image.
Another difference is the Alpha channel support for PNG which the JPG Does not
have. With the PNG images you can remove the background and save the file as a
PNG so when you reload it next time the background will always be transparent.
However if you did remove the background and then decided to save it as JPG the
file format will automatically put a white background in place.
resolution and colour depth have on file size and image quality.
Introduction
In this report I will be discussing different features of file formats that can help reduce
the size of these through different compression methods such as Lossless and
Lossy. I will then go on to talk about the impact of colour depth, image resolution and
quality for an image. However first I will pick two file formats such as JPEG and PNG
state the features and then compare them both on different levels.
File format: JPEG vs PNG
What’s a JPEG?
JPEG Is a file format that is normally used for Photographs however it can also be
used for other things. This type of format is normally a compressed image file (lossy)
however the how much the file is compressed can be altered to still obtain good
image results but a lower file size. Furthermore it is not normally limited in the
amount of colours it can support which is 16.7 million colours hence why it’s normally
used in Photographs and also most software programs support it as it is a file
extension that is used worldwide as a standard. JPEG is normally represented by the
file extension .jpeg.
What’s a PNG?
PNG File format was introduced in 1994 and is normally used in Icons because it
supports transparent/ alpha channel images which means the background will not
show. It is not used in Photographs too much because of the compression method
which usually outputs the image at a lower quality. PNG has lossless compression
which will reduce the original file size to make it smaller so sometimes you will notice
that some of the file sizes are quite small normally under Kilobytes however with this
the quality of the image will get reduced drastically so if you zoomed into the image
you will see many pixels. The good thing about PNG is it supports 24 and 32 bit RGB
colour pallet which is similar to JPG so again around 16.7 million colours and also
grayscale images. PNG is normally represented by the file extension .png.
Main differences
The main difference between the two image file formats is the type of compression
that is taken place. JPG which uses Lossy Compression which is useful as it helps
remove unimportant data which has not effect on the images representation however
if you did decided to zoom into the image it will look pixelated and blurry. PNG on the
other hand supports Lossless compression which makes sure the image is not
missing a single bit of data so when the image is represented although you might not
see any effect when you zoom in it will not look as pixelated as the JPG Image.
Another difference is the Alpha channel support for PNG which the JPG Does not
have. With the PNG images you can remove the background and save the file as a
PNG so when you reload it next time the background will always be transparent.
However if you did remove the background and then decided to save it as JPG the
file format will automatically put a white background in place.
