Re: Thumbnails

by Charles A Upsdell <cupsdell(at)upsdell.com>

 Date:  Thu, 20 Apr 2000 23:46:58 -0400
 To:  hwg-basics(at)hwg.org
 In-Reply-To:  icx
  todo: View Thread, Original
At 08:51 PM 04/20/00, you wrote:
>Need some advice about thumbnails.  I thought they were all one size
>until I started browsing the web.  Is there a program/specific way to
>make them, or do you just resize any picture until it's "small"?  I have
>Paint Shop Pro but couldn't find a "thumbnail" feature in it.

Are you producing thumbnails for your own reference purposes?  Or are you 
producing them for websites, to be clicked on to see larger images or 
related information?

If it is the later, then I would comment that producing good thumbnails is 
an art that requires practice.  It cannot be automated.  Here is what I do:

1.  Start with the highest quality image available.  Defects in the 
original will only be magnified in the thumbnail.

2.  Crop what does not need to appear in the thumbnail:  the thumbnail need 
not show the entire image; it can instead show a critical portion of the 
image.  E.g., if the original image were that of the Mona Lisa, you could 
crop off everything but the head and shoulders ... or in some cases crop 
off everything but the smile!  Be creative.

3.  Reduce the image size.

4.  The result is often blurred.  Try sharpening it with the unsharp mask 
function.

5.  If you plan to produce a JPEG, and any portion of the image is a flat 
colour - or nearly flat - use the randomize function to produce more 
variation in that portion of the image.  For example, if a portion of the 
image is the sky and is pretty well the same shade of blue, select that 
portion and apply the randomize function:  basically you should try to 
increase the variation in colour without distorting the image.  JPEG 
compression introduces severe artifacts in flat portions of the 
image:  randomizing the flat area a bit before-hand can significantly 
decrease the artifacts and enable you to use higher compression factors.

6.  If you are going to produce a JPEG, you may find it useful to intensify 
the colours:  my experience is that JPEG compression often makes the image 
duller, so intensifying the colours before-hand can compensate for this.

7.  Then (assuming you have PSP6), use the File Export function to generate 
the JPEG or GIF file.  Use this rather than File Save, because with File 
Export you can preview what the image will look like using various 
compression factors.

8.  If need be, go back a few steps and repeat, with a little variation.

E.g., I used this technique in:

     http://www.NorthAmericanDecal.com/
     http://www.adams.to/site/gallery.htm

- HTH, Chuck Upsdell

-
Chuck Upsdell
Email:     cupsdell(at)istar.ca or cupsdell(at)torfree.net
Website:   http://home.istar.ca/~cupsdell/

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