nory wrote:
Thanks for the visual. That actually really helps me understand it, I can see that its actually quite literal - ie: the "compression" version is obviously compressed and the uncompressed version its less defined. I guess its like pointalism, the more points you use in doing a picture the more realistic or smooth it will look (less like pointalism from a distance) etc...
Thanks again for taking the time to help me and explain all of this!! !
Alex is right. They are both compressed, JPEG by definition is more efficient that standard bitmap. There are lot of different types of compression and space saving algorithms available. Some are purely for speed/performance others try and focus on quality, some are somewhere in between. There is also progressive JPEG, which allows the image to download and display on screen progressively, like a window blind coming down.
GIF is generally not as efficient as JPEG. You will generate a large file if you try to save photo with GIF. However when there are few colours or small bit pixel data GIF can be more efficient.