Flash is the most versital of all the image formats currently on the web. There are few reasons for that:
1: It supports lossy compression (Like JPG)
2: It supports lossless compression ( Like PNG )
3: It supports mathmatical vector based compression for illustrations.
4: It allows for lossy compression with transparency which is not currently found anywhere else natively on the web.
.JPG compression works on a lossy / averaging algorithm. It divides the screen in to blocks and then averages the information inside those areas based on color, contrast , hue, and saturation. Hard lines and edges become blurry because they are averaged into the areas next to them.
.GIF compression works on a Loss-less algorithm, with the limitation of 256 colors. It compresses files by looking for reoccurring color information across a horizontal scan line of an image. If it detects that there are 200 pixels of the same color replicated across the horizontal scan line, it only keeps the information for that color along with a factor( representing the repetition) So with application screens, there is a lot of reoccurring color sets, therefore better compression than JPG files and better quality.
.PNG compression works on a Loss-less algorithm, with support for 32, 24, 16, and 8 bit color information. Its compresses files very similar to .GIF , except it also looks on the vertical scan line for re-occuring color information, thus increasing compression without quality loss. It allows for a 1bit transparency like .GIF files, and it also allows for a 8bit transparancy on 24bit images ( 24bit + 8 bit transparancy = 32bit ) With the 8 bit transparancy there are 256 varying degrees of transparancy that can be used on an image….this allows for semi-transparancy that is not found in .GIF files.
.SWF compression works off of either .JPG compression schemes or .PNG compression schemes. It also does good job of compressing vector-baed illustrations. For screen captures you will want to use the Loss-less PNG compression scheme. For photograpic content you will want to use .JPG compression. ***Remember, if you import a 32bit .PNG file into Flash, you can set the publishing of the file to compress the photo using JPG compression, and still keep the transparancy. This is a huge differeitiator for FLASH .SWF files with embeded images.
For Photographic content:
| |
Color Depth |
Compression |
Animated |
Email Support |
Print |
Security |
| .JPG |
24bit |
Best |
No |
Yes |
Good |
- |
| .GIF |
8bit |
Bad |
Yes |
Yes |
Bad |
- |
| .SWF |
24, 32bit |
Good |
Yes |
No |
Bad |
Best |
| .PNG |
8,24,32
Bit |
Fair |
Not Currently |
Not in major email clients |
Best |
- |
For flat artwork and screencaptures:
| |
Color Depth |
Compression |
Animated |
Email Support |
Print |
Security |
| .JPG |
24bit |
Bad |
No |
Yes |
Bad |
- |
| .GIF |
8bit |
Good |
Yes |
Yes |
Fair |
- |
| .SWF |
24, 32bit |
Best |
Yes |
No |
Good |
Best |
| .PNG |
8,24,32
Bit |
Best |
Not Currently |
Not in major email clients |
Best |
- |