I found this on Facebook, I’m not sure who the original creator was.
The difference should now be clear.
A big thanks to Colin for putting me on to this YouTube channel. As we saw in today’s lesson computer images (digital) can be very large. In order to save space when we save them we must compress them. We can either do this in a lossless fashion or in a lossy fashion. With lossless you can always get back to the original without any corruption this is not possible in lossy compression.
[kml_flashembed movie="http://www.youtube.com/v/Lto-ajuqW3w" width="425" height="344" allowfullscreen="true" fvars="fs=1" /]
There are loads of articles comparing graphic file types examples can be found here and here. I don’t intend to add to this again. However, here are the graphic examples I was using in class. The resolution remains unchanged for each but the colour depth is decreased for the GIF (which has a max of 8bit colour).
We have been going over this for a while now and I have written a helpful posting over in the Information Systems blog.
Let me give you a comparison
JPG – 9.33KB
PNG – 48.1 KB
I have turned the compression up on the JPG to show that it uses lossy compression. Download the images and use an image editor like irfanview to zoom into the pictures to check their quality.