Images display intermittently in ASP 3.0 page

I have an ASP 3.0 website on which the images are displaying intermittently.

In other words, when I request a page, the image is blank. There is no
missing image place marker (rectangle with a red X).

The location where the image should be is just empty.

The code is there to display the image as can be seen when you view source
in the browser

And if you later return to the page, or sometimes if you simply refresh it,
the image will render properly.

What could be causing this erratic behavior?

I'm not sure whether this is an ASP issue, an HTML issue, a browser issue
(the error occures in IE 6.0) or possibly a network issue.

Any thoughts are appreciated.

Thanks
Dave

Re: Images display intermittently in ASP 3.0 page

Here is some follow up information to my original post.

This evening I tried to access the web page from home. In 60 tries I was
unable to reproduce the error (i.e., all images were always displayed
properly).

At the office where I encountered the error I am using IE 6.0. At home
where I am not encountering the error I am using IE 7.0 (i.e., Mozilla/4.0
(compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR
2.0.50727; InfoPath.1))

I did an analysis of the site statistics and found 4 user sessions today
where the user was referred to the site, made multiple requests for the same
question in rapid succession and then left.

This behavior is consistent with the problem I am seeing; that some images
are not being displayed on the page so the user tries to refresh the page
several times and when he is unsucessful, gives up and leaves,

If anyone has time, they can try to reproduce the error by going to
http://www.frickcpa.com/tvom/TVOM_Answer.asp?qno=10

At the office I can always produce an errror within abount 2 dozen tries.

I load the page and then click the HP-12C link near the bottom. I should
see two graphics for Question 10, each with an image of the HP-12C
calculator at the top, followed by images of a set of key strokes.

Sometimes I see both images, sometimes I see one, sometimes I see a partial
image and sometimes I see only the text with no images at all.

I never see a missing image icon (rectangle with a red x), just a gap where
the image should be. As I said previously, if I go into the brower's view
source, I see all of the HTML code to render the image; it's just not being
displayed. If I keep refreshing the page, the image eventually displays.

This problem has me perplexed because I have not encountered it on other
sites. In other words, I can't ever remember going to a site where there
were big blank gaps where the images should have rendered, I've seen
missing image placeholders before but not just empty spaces.

Any thoughts are appreciated.

Re: Images display intermittently in ASP 3.0 page

Dave wrote on Wed, 5 Sep 2007 21:43:50 -0700:

> If anyone has time, they can try to reproduce the error by going to http://www.frickcpa.com/tvom/TVOM_Answer.asp?qno=10

The images appear to be just references to GIF files. If these are just
pulling the GIFs direct from IIS, and they're not being generated via ASP
(eg you have isapi_rewrite running and the GIFs are actually generated on
the fly by ASP code), then you'd be better off posting in an IIS group as it
won't be an ASP issue.

Check the logs to see if there is something odd going on with the requests
for the images (ideally with a request from you when it goes wrong so you
know that it's actually failed). Do you have any sort of proxy/caching
server in front of your IIS server that might be serving empty images?

Also, when you get blank images, go to your Temporary Internet Files folder
in IE and try to find the cached image files, copy them somewhere else (so
they don't get removed), and then take a look at them using a graphics
editor/hex editor to see if maybe there's some sort of corruption going on.

One other thing to check - does your IIS have HTTP Compression enabled?
Maybe that's corrupting the images so they're actually being delivered to
the browser, but due to being corrupt it's unable to actually display it
correctly and just shows a blank area.

Dan

Re: Images display intermittently in ASP 3.0 page

"Dave" wrote in message
news:OXRLR$D8HHA.1416@TK2MSFTNGP03.phx.gbl...
> Here is some follow up information to my original post.
>
> This evening I tried to access the web page from home. In 60 tries I was
> unable to reproduce the error (i.e., all images were always displayed
> properly).
>
> At the office where I encountered the error I am using IE 6.0. At home
> where I am not encountering the error I am using IE 7.0 (i.e., Mozilla/4.0
> (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR
> 2.0.50727; InfoPath.1))
>
> I did an analysis of the site statistics and found 4 user sessions today
> where the user was referred to the site, made multiple requests for the
same
> question in rapid succession and then left.
>
> This behavior is consistent with the problem I am seeing; that some images
> are not being displayed on the page so the user tries to refresh the page
> several times and when he is unsucessful, gives up and leaves,
>
> If anyone has time, they can try to reproduce the error by going to
> http://www.frickcpa.com/tvom/TVOM_Answer.asp?qno=10
>
> At the office I can always produce an errror within abount 2 dozen tries.
>
> I load the page and then click the HP-12C link near the bottom. I should
> see two graphics for Question 10, each with an image of the HP-12C
> calculator at the top, followed by images of a set of key strokes.
>
> Sometimes I see both images, sometimes I see one, sometimes I see a
partial
> image and sometimes I see only the text with no images at all.
>
> I never see a missing image icon (rectangle with a red x), just a gap
where
> the image should be. As I said previously, if I go into the brower's view
> source, I see all of the HTML code to render the image; it's just not
being
> displayed. If I keep refreshing the page, the image eventually displays.
>
> This problem has me perplexed because I have not encountered it on other
> sites. In other words, I can't ever remember going to a site where there
> were big blank gaps where the images should have rendered, I've seen
> missing image placeholders before but not just empty spaces.
>
> Any thoughts are appreciated.
>

Works fine for me IE6 on 2000 and IE7 on XP.

Is the blank gap the right size for the image?

Sounds like a browser problem to me, its very doubtful that ASP or the
network is to blame.


--
Anthony Jones - MVP ASP/ASP.NET