Lesson 1 Extra Credit

Comparing File Sizes of Different Formats - JPEGs

Click on the thumbnail to see the original graphic.

Again, here is the original graphic - filesize1.psp.
Size is 206 x 206, 72 pixels/inch, 16M colors, 1 layer.
When displayed in PSP 5 it is 124kb.
Saved in PSP format at 107kb.

Here are examples of filesize1.psp saved in different JPEG compression formats. File display size, file store size, and loading times are given. Because JPEG compression is a "lossy" type of compression, graphic detail is degraded when this format is used.

Note that in the maximum compression graphic (filesize1c.jpg), alot of detail has been lost.

Also note that standard encoding was used in all three graphics. I did compare file size and loading time between the standard and progressive encoding forms and there was no difference. The only thing progressive encoding did was change the way that the graphic loaded.

filesize1a.jpg

No color reduction.
Minimum compression. Standard encoding.
Resolution 72 x 72 dpi
Displayed size = 124kb
File size = 34kb
Loading time at 28.8 bps = 9.9 sec

filesize1b.jpg

No color reduction.
50% compression. Standard encoding.
Resolution 72 x 72 dpi
Displayed size = 124kb
File size = 8kb
Loading time at 28.8 bps = 2.3 sec

filesize1c.jpg

No color reduction.
Maximum compression. Standard encoding.
Resolution 72 x 72 dpi
Displayed size = 124kb
File size = 2kb
Loading time at 28.8 bps = 0.4 sec