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Date Posted: 19:26:18 11/26/02 Tue
Author: Todd Cary
Subject: Re: Size of resized image files
In reply to: Michel 's message, "Re: Size of resized image files" on 17:47:43 11/26/02 Tue

First I convert the jpeg image to a bmp, then I use Melander's Stretch for the compression. Lastly, I set the Quality to 100 and convert the bmp back to a jpeg.

Isn't this the maximum quality that I can use?

Todd
>
>Hi Todd,
>
>First, BMP files usually don't have any compression,
>so true color files are generally very large as Bmp.
>BMP files may have RLE compression but it is not very
>good and it not used very often.
>
>When saving as JPEG it is another story. JPEG uses a
>lossy compression (you lose image quality, sometimes
>not noticable). But if you continously open and save a
>JPG file you will see the degradation. This is why it
>achieves great compression. Also, there are difference
>between jpg compression because jpg has a quality
>factor which you can change while saving. Better
>quality means less compression. This is probably the
>difference between Envision and photoshop. See the
>TJpegGraphic.SaveQuality property in the help file.
>
>Best regards,
>
>Michel
>
>
>>If I use one of the filters to resize an jpeg image
>>(750 X 450), I get approximately a 25 K file. The
>>intermediate bmp file (if I save it for debugging
>>reasons) is 18 MB.
>>
>>When I use PhotoShop to resize the same image, it is
>>approximately 250 K. Why the difference?
>>
>>Todd

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