Re: Image sizes

Hi Greg,

I have here a dejavu, or as I put it we have been there and back again,
though on other topics on formats.

1) It is possible to integrate different images sizes(resolutions) into epubs
     and link through!
     The disadvantage to this direct approach is not the epub become large:
      duplicity of image files.

2) One can use a good quality images and have it adjusted to screen size
     The problem here is that depending on the device used they will
      need time to render.

3) Some devices allow one to zoom into a image, not necessarily a link
     Advantage one image, Disadvantage as under 2)

4) One can use high quality images and use compression two reduce file
     size.
     Disadvantage as under 2.

5) using 4) one can use a link to a better/ larger version
    disadvantage as under 2
     some reduction to displayed quality of the image
    Advantage smaller  Epub size, just one image file!

6)  Resolution
     A big can of worms could right a whole essay on this
     The pixel size of a image influences its the file size of an
     image. This actually does tell us much about the quality
     of an image, because it depends on the resolution and size 
     of the device use to display it. Furthermore, it also depends
     on the software used! (An old rule of thumb for high quality
     printouts on good printer was to use 1.5 to 2 times printer
     resolution)

      Even though resolution impacts on file sizes depending on the format
      and compression rate used one can have better control of file sizes.
      
     
As far as b) is concerned it depends on the device! 

Another aspect is: What do we call a dedicated ereader and and what not!

As I mentioned on another post to this thread the source for and epub
CAN be designed to work well images of different resolution and one can create Epubs with different
versions of the graphics. 

regards
	Keith.

Am 28.01.2014 um 06:31 schrieb Greg Newby <[email protected]>:

> I would welcome someone taking an attempt to turn this
> into rewritten guidance for the FAQ.  Seems there are some nuances...
> 
> I don't really use the epubs that much.  Can someone mention how well
> things work if we use medium-resolution images, that can click to high
> resolution images?  (a) are they all just packaged in the .epub,
> regardless, and (b) once the image is downloaded to a device, are
> large images a problem to display (i.e., slow due to file size)?
> 
> For phones, limited bandwidth etc., presumably people who are
> reasonably concerned and/or experienced will just select the version
> without images.
> 
>  -- Greg

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