This morning a SPORRS List subscriber asked me a very good question, and
since others have asked me about this to some degree as well, I thought it
beneficial to post the answers to the list.  

That question:

> ...any chance of more thumbnails and less graphics load to make the 
> thing faster?

Answer:

No, unfortunately.  The question contradicts itself in a way, but I'll try
my best to explain:

The current graphics (non-photo logos) have no noticeable effect on page
loading time for reasons described below, but the RR pictures do, even with
the smallest file sizes useable, which is what we are using.  Any smaller,
and our images would no longer resemble photographs, but rough jagged
graphics instead.  Also, any time more images are added (like separate
thumbnail files - explained below), the site will just get slower, not
faster.  And the key to making pages load quickly around the pictures is to
define each images' size in pixels on the HTML source code, so that the
rest of the page can load without uninterruption around the exact pixel
spaces that the images will follow into.  Some basic 
understanding of HTML would be helpful here, and this issue of thumbnails
and file size is described in the SPORRS News Section on the web site
somewhat, but here's more:  

The first SPORRS (home) page (the one with all of our pictures on it) loads
slow because all of the image files (which are used for both the thumbnails
and the larger sized pictures that they link to) have to load on that first
page or there wouldn't be any pictures on it.

So... Next Question:

> can you use smaller files for the thumbnails, like GIF files?

Answer:

GIF files of the size we need are actually bigger than JPG files and look
worse.  GIF files are usually just used for logos with a limited amount of
colors in them.  I could use much lower quality GIFs (with less colors) for
the image thumbnails, but the JPG files would still be required for the big
images, so that would not make them load any faster in this case.  It would
actually make the site slower to use by adding more files to load, and in
order to make a smaller file size (in kilobytes) GIF thumbnail, it would
have to be of such poor quality that you wouldn't be able to identify what
most of them are.  (And the JPG files are still required for the big
images).  A full color (256) GIF file contains less colors and image data
in it than a JPG, and actually takes up more file space than a JPG, because
JPG files are highly compressed.

When you see GIF files (like the SPORRS logos) first appear fuzzy and then
get sharper as they load, this is because the file is 'interlaced' and
loading in layers.  This 'interlaced' type of GIF does not actually load
any faster than any other, but it can help the rest of the page load faster
only because the image dimension is quickly defined (if it's not already
defined in the code) on the page so the rest of the page can load around
it.  All JPG images on the SPORRS site are defined in the source code by
their pixel dimensions, so there would be no benefit at all in using
interlaced GIF images for that purpose on the site.  The benefit to using a
GIF file can only be realized with images that can be displayed with the
lowest number of colors as possible.   

The current JPG files are pulling 'double duty' by being used for both
thumbnails and full images from the same single file for each image.  After
the first page loads, they are already downloaded in your cache so you can
then quickly click from one image to the next without waiting for anything
else to load.  Otherwise, you would have to wait for EACH image to load
separately when you looked at each one.  If we want to have our thumbnail
selections and see big images too, then we have to wait for them to load at
some point.  Waiting initially for the site to load can be frustrating with
a slow modem, but this is still generally less objectionable than waiting
for EACH image to load as you view them one at a time while having less
images to select from as well.

Question:

>can you put all the pictures on another page of the web site?

Answer:

If I move all of the images to a separate page in the site, then the first
page would load in a snap, but it would contain no RR pictures, and in this
example, when you would go to that separate page to look at the images,
then you would have to wait, just like now, but one at a time, to see any
image (with nothing else to read while you would be waiting, because if you
would go back a page to the first page at that point, then that second
image page would stop loading).  A page only loads when you are on it.  If
you haven't visited a particular page on a site yet, then you must wait for
each page to load as you visit each one.

I hope this answers some of your questions.  Subscribers input welcome.

Regards,

Dave Cohen
Photographer
[EMAIL PROTECTED]
http://home.att.net/~acphotog
SPORRS: http://home.att.net/~acphotog/sporrs/sporrs.htm
--> SPORRS: Serious Photographers of Railroad Related Subjects

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