File Compressions Lossy/Lossless

File compression is simply a special formula know as algorithm used to create smaller files. The reason for compressing files is that some graphic files are big and take up a lot of space on computers and if I was downloading a big file it would take a long time for the file to finish. Though compression is good for space, the greater the compression the poorer the quality of the image so I would try the balance the quality of the file size.

 

There are two types of compression, lossy and lossless.

 

Lossy compression offers a greater compression than lossless and some of the pixels of the image will be changed while making the file size smaller. The important thing knowing about lossy compression is when it assumes some of the data that isn’t important it cuts out the unimportant data and that data is permanently lost. JPEG and Bitmap images uses this compression.

 

Lossless compression is different because when compressing none of the data gets lost in fact the data can be used to rebuild the image to its original quality. It uses mathematical functions to eliminate redundant data and if there isn’t enough redundant data then the file size may not be significantly reduced. There are much different graphic software that uses lossless compression such as WinZip and Stuffit. GIF and PNG images use these compressions.

 

Here is a diagram I found at https://wikis.glowscotland.org.uk/@api/deki/files/18430/=LOSSY.GIF that will help explain how lossy and lossless compressions work.

 

It shows that when you do a lossless compression and restore it all the data is still the same as from the original and while using lossy compression and restore, it loses data from the original.