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Image resizing

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Category: General Discussion
Forum Name: ASP.NET Discussion
Forum Description: Discussion and chat on ASP.NET related topics.
URL: https://forums.webwiz.net/forum_posts.asp?TID=7353
Printed Date: 29 March 2026 at 1:25pm
Software Version: Web Wiz Forums 12.08 - https://www.webwizforums.com


Topic: Image resizing
Posted By: ultramods
Subject: Image resizing
Date Posted: 18 November 2003 at 4:46am

I have currently been using asp jpeg to resize images to create thumbnails. However i wish to use some .net enabled hosting which doesnt use this component. I have never used .net before but have found this script for resizing images and would just like to know if this script would actually work before I buy the .net space. Thanks for any help given on this.

' Initialize objects
Dim objImage, objThumbnail As System.Drawing.Image
Dim strServerPath, strFilename As String
Dim shtWidth, shtHeight As Short    
' Get image folder path on server - use "\" string if root
strServerPath = Server.MapPath("WebAppImageFolder\")
' Retrieve name of file to resize from query string
strFilename = strServerPath & Request.QueryString("filename")
' Retrieve file, or error.gif if not available
Try
    objImage = objImage.FromFile(strFilename)
Catch
    objImage = objImage.FromFile(strServerPath & "error.gif")
End Try
' Retrieve width from query string
If Request.QueryString("width") = Nothing Then
    shtWidth = objImage.Width
ElseIf Request.QueryString("width") < 1 Then
    shtWidth = 100
Else
    shtWidth = Request.QueryString("width")
End If
' Work out a proportionate height from width
shtHeight = objImage.Height / (objImage.Width / shtWidth)
' Create thumbnail
objThumbnail = objImage.GetThumbnailImage(shtWidth, _
  shtHeight, Nothing, System.IntPtr.Zero)
' Send down to client
Response.ContentType = "image/jpeg"
objThumbnail.Save(Response.OutputStream, Imaging.ImageFormat.Jpeg)
' Tidy up
objImage.Dispose()
objThumbnail.Dispose()




Replies:
Posted By: Mart
Date Posted: 18 November 2003 at 10:30am
Yes it will work, it uses standard system.drawing namespaces.


Posted By: ultramods
Date Posted: 18 November 2003 at 12:30pm
Ok, thanks for that Mart.


Posted By: Diam
Date Posted: 27 November 2003 at 3:35am

Hello everybody,

I need your help for something similar.

I would like generate a thumbnail of a picture (.jpg) located on the webserver, but unfortunately my hosting do not allow me to register any component.

It seems it's not possible to do that only with ASP (without component), but only with ASP.Net, but unfortunately, I'm not able to write any line with ASP.Net by myself.

What I could to, it's save the image to resize on a specific folder, call an ASP.Net page with few parameters : the path of the image, a return code (if error ?), the max size (width, height), ... and an URL where to go after the operation is complete).

It could be also very good to allow to know the size (width, height) of a picture with another page (and return it in a parameter)...

What do you think about that ? Anyone who could help me to do that ?

Thanks a lot for your help !



Posted By: Mart
Date Posted: 27 November 2003 at 9:23am
Use the code posted above!


Posted By: Diam
Date Posted: 27 November 2003 at 12:18pm

But, this page generate a thumbnail and send it to the client... what I would like, if it's possible, it's to write it on the webserver... (I don't want the webserver need to generate the thumbnail everytime someone want view it...)

For exemple...

- Form1.asp (a form where it's possible to post a picture).. submited to "saveImage.asp"

- saveImage.asp, a page which make the upload, save the pic on the webserver... then, at the end, response.redirect "generateThumb.aspx?imgsrc=image.jpg&gotoURL=displayMess age.asp" for exemple

- generateThumb.aspx, a ASP.Net page, who generate the thumbnail "image_tn.jpg" and save it on the webserver... then, redirect to "displayMessage.asp"

- displayMessage.asp, display a message, for exemple, "Image successfully saved..."

I admit I'm not able to write ASP.Net pages, sorry...

Thanks for your help !



Posted By: Mart
Date Posted: 27 November 2003 at 1:47pm
Change the line
objThumbnail.Save(Response.OutputStream, Imaging.ImageFormat.Jpeg)

to

objThumbnail.Save(server.MapPath("test.jpg"), Imaging.ImageFormat.Jpeg)


Posted By: Diep-Vriezer
Date Posted: 27 November 2003 at 3:35pm
Originally posted by Diam Diam wrote:

But, this page generate a thumbnail and send it to the client... what I would like, if it's possible, it's to write it on the webserver... (I don't want the webserver need to generate the thumbnail everytime someone want view it...)

For exemple...

- Form1.asp (a form where it's possible to post a picture).. submited to "saveImage.asp"

- saveImage.asp, a page which make the upload, save the pic on the webserver... then, at the end, response.redirect "generateThumb.aspx?imgsrc=image.jpg&gotoURL=displayMess age.asp" for exemple

- generateThumb.aspx, a ASP.Net page, who generate the thumbnail "image_tn.jpg" and save it on the webserver... then, redirect to "displayMessage.asp"

- displayMessage.asp, display a message, for exemple, "Image successfully saved..."

I admit I'm not able to write ASP.Net pages, sorry...

Thanks for your help !

Why don't you use .NET for all of this? The pages are all quite simular. You can actually create the images at runtime, but the image url whould have to be set to Image.aspx?Mode=Thumb&ID=838-394. This will generate a thumbnail at the servers cache, and return it to the user. The ID represends the image name, not included the .JPG tag. The mode can be set to anything you'd like.

That's how I would do this thing.



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Gone..



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