Generating .Gif images on the fly, tips needed

[Anton]

hi

asp.net

I'm trying to generate images which can be used inside email and not giving
warning about phishing. So to avoid that I need the image to be a regular
image. Not like Show.aspx?=31. Outlook don't like images with the ?= in it's
filename.

Okay, when changes to the image the for example I could store the image on
the server. Like Anton.gif, then just access Anton.gif directly.

But I have another problem which makes this a bit more complicated for me:
The image I don't want it to be in the cache for more than an hour or so
before it is reloaded again. Then I'm not sure how Anton.gif can solve that!
I just came accross Response.Expires, maybe that property can help me?

The reason for the cache expiration is that the image is hosted on internet.
When image is updated then I want the email to display the updated version
instead of a cached version.

any ideas?

 

[Patrice]

Hi again,

IMO images are blocked based on the content/type not depending on the URL.

It will work only in edge cases as most client are blocking images and a
mail doesn't have a refresh concept as it is "static" by design (could work
mostly on web client).

Even when possible, I find highly questionnable to change even a part of the
email content without the user consent... (I saw that you want to do in an
earlier thread). What if the system is abused by changing the signature
let's say with a porn image. What if I wanted to see the mail unchanged to
get in touch with the company you were before, not you personanly etc...

 

[Abe Simpson]

AspEmail (www.aspemail.com) allows you to send embedded images, not linked,
so you don't have to worry about phishing.

AspJpeg (www.aspjpeg.com) allows you to generate GIFs on the fly and you can
attach those to AspEmail-generated messages via memory, without creating
temporary copies of the images on the server's disk.

-- Abe

 

[Gregory A. Beamer]

AspEmail (www.aspemail.com) allows you to send embedded images, not
linked, so you don't have to worry about phishing.

AspJpeg (www.aspjpeg.com) allows you to generate GIFs on the fly and
you can attach those to AspEmail-generated messages via memory,
without creating temporary copies of the images on the server's disk.

The OP wants the image to be up to date when the person reads the email.
IE, if the email is sent and the user changes the image, he wants the email
recipient to get the newly saved image and not one previously sent in an
email.

peace and grace,

 

[Gregory A. Beamer]

hi

asp.net

I'm trying to generate images which can be used inside email and not
giving warning about phishing. So to avoid that I need the image to be
a regular image. Not like Show.aspx?=31. Outlook don't like images
with the ?= in it's filename.

Okay, when changes to the image the for example I could store the
image on the server. Like Anton.gif, then just access Anton.gif
directly.

But I have another problem which makes this a bit more complicated for
me: The image I don't want it to be in the cache for more than an hour
or so before it is reloaded again. Then I'm not sure how Anton.gif can
solve that! I just came accross Response.Expires, maybe that property
can help me?

The reason for the cache expiration is that the image is hosted on
internet. When image is updated then I want the email to display the
updated version instead of a cached version.

By default, GIF images do not cache on the server side. If you want to
explicitly turn off caching for the site in question (the site serving
the images) you can ensure everything does not cache.

As for client side caching, you have very limited control over it. And,
since images don't have an expire, per se, you can't expire them on the
client side if the person is directly linking to the image.

In general, this will not be a problem, as you will update the image,
which updates its changed date, so when the request is made, the answer
is that there is a new image if a new image was saved. If the user has
it set to not check, it will pull from their cache regardless and there
is nothing you can do about it.

In short, you can spend a lot of time trying to solve the "caching"
problem and still end up bust on this one, as the user has control over
his own cache.

Peace and Grace,