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For JPEGs, you can adjust the 'image quality' of the JPEG. Typical JPEGs are at %75. By saving a file at %50 you can decrease the image size. |
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GIFs allow for size tuning by reducing the number of colors in the image. |
For many HotMedia projects, the designer has the flexibility to choose specific compression settings for individual components of the HotMedia. The more common file formats supported are JPEG and GIF. Each of these formats has parameters which can adjust the resultant image quality and file size.
To appreciate quality vs. size tradeoffs, we will utilize the 'same' HotMedia experience, but adjust sizes and quality. This is a simple artificial example which can be used as a guide to experimentation with the various parameters.
Remember, HotMedia supports both JPEG and GIF, so image content will influence your choice of compression. For animated sequences where you do not expect the user to view interim images, reducing quality may be an acceptable way to reduce the overall HotMedia file size without compromising the complete experience.
If you try to import a transparent GIF, you will see a warning screen notifying you that you may not get the desired results. The image may have additional artifacts. This is Java functionality.
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For JPEGs, you can adjust the 'image quality' of the JPEG. Typical JPEGs are at %75. By saving a file at %50 you can decrease the image size. |
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GIFs allow for size tuning by reducing the number of colors in the image. |
The following table compares some file sizes.
Note: This example should not be used to compare JPEG and GIF image quality. Photographs, or other high color images would compress much better with JPEG compression than GIF. This is simply meant as an exercise to remind the HotMedia author that compression quality can be sacrificed for file size.
| File Name | Format | Size in Bytes | Image Example |
|---|---|---|---|
| samples00.BMP | Bitmap |
30,056 |
Not visible in browser! |
| samples00_2.gif | 4 color GIF | 624 |
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| samples00_3.gif | 16 color GIF | 787 |
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| samples00.gif | 256 color GIF |
962 |
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| samples00_25.jpg | 25% JPEG | 1,147 |
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| samples00_50.jpg | 50% JPEG | 1,399 |
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* These recommendations are not intended as full discourse on image manipulation, but instead prescribe some common approaches to image file adjustments so as to improve the overall HotMedia experience.