posted 12-16-2003 10:35 AM            

The are many image file types and each type (i.e., gif, jpg, tif, bmp, png, etc.) has their particular uses (advantages and disadvantages). Most photos are posted in the JPEG format (.jpg or .jpeg).

Depending on the image editing software you use when saving a photo into a JPEG file it will give you the option to compress the file. Some photos compress better than others. Why compress a photo image? Reducing the file size speeds up the time it takes to transmit/display the image.

Here is an example:

1. maxium compression
   490 pixels wide X 135 pixels high at 72 dpi
   file size on disk: 11k
   image size displayed: 192k
   

2. 50% compression
   490 pixels wide X 135 pixels high at 72 dpi
   file size on disk: 17k
   image size displayed: 192k
   

3. no compression
   490 pixels wide X 135 pixels high at 72 dpi
   file size on disk: 69k
   image size displayed: 192k
   

Can you see a significant difference in image quality (for use on the forums)?