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Image Distortion

Jul 21, 2011, 19:18
Post: #1
Image Distortion
ok so I am creating a slideshow with an image that was made from word changed into a pdf then to a jpeg. I have successfully created the slideshow with 4 of these images however, now these images are very distorted and the pixels looked stretched. Can someone please help me get this to a clearer image? this is for a website for my employer! ANY ASSISTANCE IS APPRECIATED! Thanks
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Jul 21, 2011, 19:39
Post: #2
RE: Image Distortion
(Jul 21, 2011 19:18)mrsmoody0507 Wrote:  ok so I am creating a slideshow with an image that was made from word changed into a pdf then to a jpeg. I have successfully created the slideshow with 4 of these images however, now these images are very distorted and the pixels looked stretched. Can someone please help me get this to a clearer image? this is for a website for my employer! ANY ASSISTANCE IS APPRECIATED! Thanks

1) forget about JPEG. Unless you have photos (but you wouldn't be using Word) the PNG format is much better (doesn't create artifacts and stray pixels). All browsers support it.
2) if your image looks elongated in one direction, it's likely because you didn't take in account the aspect ratio (width/height), in all steps so it got changed somewhere during a resize.

Please attach one of the pics here (or PM me a URL where I can see it if you don't want it going public).

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Jul 26, 2011, 16:59
Post: #3
RE: Image Distortion
I have attached two images here. The BB.gif is of the Slideshow, if you notice its quality is quite a bit less than the image alone exch.jpeg
thanks!
   
   


(Jul 21, 2011 19:39)ofnuts Wrote:  
(Jul 21, 2011 19:18)mrsmoody0507 Wrote:  ok so I am creating a slideshow with an image that was made from word changed into a pdf then to a jpeg. I have successfully created the slideshow with 4 of these images however, now these images are very distorted and the pixels looked stretched. Can someone please help me get this to a clearer image? this is for a website for my employer! ANY ASSISTANCE IS APPRECIATED! Thanks

1) forget about JPEG. Unless you have photos (but you wouldn't be using Word) the PNG format is much better (doesn't create artifacts and stray pixels). All browsers support it.
2) if your image looks elongated in one direction, it's likely because you didn't take in account the aspect ratio (width/height), in all steps so it got changed somewhere during a resize.

Please attach one of the pics here (or PM me a URL where I can see it if you don't want it going public).
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Jul 26, 2011, 19:24 (This post was last modified: Jul 26, 2011 19:26 by ofnuts.)
Post: #4
RE: Image Distortion
Ah, you didn't make a "slide show" but an animated GIF. And your image isn't distorted but pixellated, which is expected since it is a GIF. Color gradients require a lot of different tones and GIF only support 256 different colors in an image (vs the 16 millions in Jpeg or PNG). The smoothness of lines also uses carefully mixed colors in the pixels at color borders which also requires a lot of different tones

You aggravate this by putting several rather unrelated images (color-wise) in the same GIF (the 256 colors restriction doesn't apply to each frame but to the whole image, (and UniterHealthCare seems to have taken the Lion's share).

If you want to do things properly:

1) Don't even use JPEG, use PNG and make separate images.
2) Use Javascript code to cycle the images.

To do it half-properly:
- edit all images together as RGB
- convert the image explicitly to "indexed" (Image/mode/indexed), and use Floyd-Steingberg dithering
- then save as (animated) GIF

To show you the difference (all images converted back to PNG to insure perfect reproduction):

The original (artificial image made to contain many more that 256 colors):
[attachment=572]

What you get without dithering (default when you save as GIF from "RGB" mode):
[attachment=573]

What you get if you convert explicitly to indexed and use dithering:
[attachment=574]

Your image where I used dithering (using the two available images not too altered):
[attachment=575]

(note that the more frames you add, the less colors per frame will be available, if you add two more images it won't look as good anyway).

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Aug 10, 2011, 16:01
Post: #5
RE: Image Distortion
Thanks for your input in, sorry it has been awhile since I posted. Can you point me in the direction to do a Javascript code for cycling.
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Aug 10, 2011, 17:22
Post: #6
RE: Image Distortion
(Aug 10, 2011 16:01)mrsmoody0507 Wrote:  Thanks for your input in, sorry it has been awhile since I posted. Can you point me in the direction to do a Javascript code for cycling.
http://javascript.internet.com/miscellan...ycler.html

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