Re: eRPG; where are my images

John

I found that whilst Netscape would not access image with blanks in their name,
Internet Explorer would.

i.e. if any of your users use Netscape, you should use

my_image.jpg

and NOT

my image.jpg

This applies from Netscape 3.0 to 4.72 .

In addition, even the file extension must be in the correct case.

I also always send the browser the full URL with IP address for my own system 
but
with domain name for other systems.  Hans gave the example -

<img src="http://www.abc.to/dirname/images/image.gif">

(Has Toronto moved to Tonga?)

I store only

dirname/images/image.gif

for images on my own system and use code to generate the remainder including my
own system IP address.  This has the advantage of less typing and so less room
for error and if you change system, you do not need to retype all your image
URL's.  Using the IP address means that the address does not have to be looked 
up
and this should improve performance.

For systems over which I have no control, I store

www.abc.to/dirname/images/image.gif

and generate the rest.

I find jpg gives better quality images than gif.

One advantage that Netscape has over IE (apart from the fact that it is not an 
MS
product) is that if you send a larger image than you wish to be displayed
initially and generate appropriate "HEIGHT" and "WIDTH" parameters so that it is
displayed initially in the smaller size, users can right click on an image and
select "view image" in which case it will be displayed in the maximum size.  I 
am
not aware that you can do this in IE unless you send a request back to the 
server
and the server sends a larger image file.

I generally send ten images at a time, together with any data or text retrieved
from my database, and display these in two rows of five images each with their
own data.  Anyone requiring a more detailed image can just right click on it. If
I know that only one image will be sent, then I send it in the larger size.

Sending all images in larger size means that more traffic is sent down your
network when users only look at the small size but less when they look at two
sizes if you use a method that depends on sending a second file for the same
image.  I find that using jpg files with minimal quality and so maximum
compression means that a black and white image say 772 x 600 pixels is about 37k
which is not too bad on a local network and works OK over the Internet.  Colour
images tend to be larger so I reduce the maximum size when creating the jpg 
file.
Given that the quality of the very best screens is relatively poor, the
difference in image quality on a screen between pictures with zero compression
and those with maximum is not so great.  Maximum compression allows people to
look at quite large images for identification purposes yet those images are not
of adequate quality for them to steal and publish in printed form (unless on a
postage stamp).  The maximum size that you transmit will obviously depend on the
use to which the images are put.  The amount of compression that you can get 
away
with will depend on whether the image is tonal - e.g. a photograph or painting -
or is made up of lines - an engineering or architect's drawing or an etching.

I hope this helps.

BTW, can anyone tell me how to get image details such as image size from, say, a
jpg file directly into an AS/400 file.  At present these have to be typed in.

Rob Dixon

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