Graphic File Formats:

•        All comp. doc. Or files are packaged in different formats.

·      The format is determined often by the files origin, such as a software program like Photoshop, or a device such as digital camera.

·      Graphic files such as a photo, video, or artwork can be reduced in file size by using image compression formats.

• Lossy vs Lossless

·      Graphic image formats fall under two categories of compression, Lossy and Lossless.

·      With Lossy, image data is “lost” or reduced for smaller file size but can cause poor image quality. Can result in showing “compression artifacts” (pixels).

·      Lossless retains image data for higher quality but larger file size.

• Graphic Formats:

·      TIF, JPG and GIF are the three most common formats for activities such as printing, scanning and displaying images over the Internet.

·      PNG is a common web format, is high quality and can contain an alpha (transparency) channel.

·      Each format has its own advantages, disadvantages.

• TIF format:

·      Stands for Tagged Image Format

·      Common format for desktop publishing, print, photo, and graphic design.

·      Is a LOSSLESS file format. It remains image data for maximum image quality.

·      Can result in larger file sizes, not fit for display over internet, is not browser compatible.

JPG format:

·      Stands for Joint Photographers Expert Group

·      Created for digital photography and works best for photo content

·      Is a LOSSY format

·      Can reduce an image size by ten to one (10:1) without showing significant compression artifacts.

·      The level of compression is adjustable.

• GIF format:

·      Stands for Graphic Interchange Format

·      Is best for graphics or images that have flat color or even tone, such as a cartoon.

·      Reduces image size by “indexing” color from three cannels to one

·      Is adjustable by changing color bit levels from one to eight

·      Contains no DPI (Dots per Inch) data for printing. Not a proper format for print.

• Know your Pixels

·      TIF and JPG are best for images with pixels that blend in color; these are called “contiguous pixels.”

·      GIF is best for images with flat even tone, or “non-contiguous pixels.”

VW-bus-24.png  152KB

VW-bus-8-128-dithered.png  44KB

VW-bus-high.jpg  45KB

VW-bus-med.jpg   25KB 

VW-bus-low.jpg   19KB

VW-bus128-dithered.gif  48KB

VW-bus-128-no-dither.gif   47KB

VW-bus-64-no-dither.gif   33KB

VW-bus64-dithered.gif   33KB

VW-bus-32-dithered.gif    28KB

VW-bus-32-no-dither.gif    27KB

VW-bus-restrictive.gif    21KB

The VW Bus image that I think has the best quality is saved under the preset PNG-24; however it is also the largest file size. The smallest file size is the image saved under a JPG in lowest quality, but it is one of the images that has the worst quality too. The image that is the best balance of size and quality would have to be the JPG saved in high quality.