On Wed, 8 Mar 2000, Michael C. Starkie wrote:
> How does one convert a gif image to jpeg? The save-as option for jpeg
> is disabled when viewing my gif image.
>
The difference between gif and jpeg are fundamental. Gif images use
indexed colours. That means that you tell the image editor how many
colours to save (between 1 and 256) and that's all the colours you may use
in the image. So if you have a photograph (which generally uses 16
million colours) and cut it down to 4 colours, you will have a very
strange image. Gif compression is best for images with a small number of
solid colours and little or no gradiation. For instance, a white block of
text on a red and black striped background would be best for a gif image.
Just a tip - never do your development in indexed colours. Use the RGB
original and convert to indexed colours as a final step before saving.
Jpeg images use another form of compression. Rather than limiting the
number of colours you may use, it actually sacrifices image quality. This
is why you may specify the compression ratio. The tighter compressed, the
worse the image. Low compression generally means that you may see almost
no difference in the compressed image and the original. Jpegs use full
RGB colour rather than a selected index. This compression works best for
images with a large colour spectrum and lots of gradiation. I tend to use
the jpeg format most for photographs.
In order to convert from gif to jpeg, you will need to convert from
indexed to RGB colour. In most versions of GIMP, this is done by
right-mouse-clicking and selecting image->rgb.
Good luck with your images. Hope that's helpful!
--Ames
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"Fine! Then I'm just gonna take my laptop and go home!!!"
Amy L. Abascal [EMAIL PROTECTED]
Web Design Chic, VA Linux Systems www.valinux.com
Web Design Chic, Silicon Valley Linux Users Group www.svlug.com
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