How can I check and validate dimensions of a picture before upload?

[Pedro]

In my web application I use a AsyncUpload to load the picture of each user to their personal page.
I need to limit the dimensions (height and width) of uploaded images.

How can I validate the height and width of the images before they are loaded? Or convert them to the dimensions I want?
I need images have the dimensions 150x100
I have the following code to validate file type and file size of uploaded images.

foreach (UploadedFile file in LogoUpload.UploadedFiles)
    {
        //string filetype = LogoUpload.PostedFile.ContentType;
        string filetype = file.ContentType;
        long filesize = file.ContentLength;
        byte [] input = new byte[filesize - 1];

        long maxFileSize = 1024;

        if (filesize > maxFileSize)
        {
            base.OnUIValidation("The file is too big.");
            return;
        }

        string[] acceptedFileTypes = new string[3];
        acceptedFileTypes[0] = "image/jpg";
        acceptedFileTypes[1] = "image/jpeg";
        acceptedFileTypes[2] = "image/jpeg";

        bool acceptFile = false;


        //should we accept the file?
        for (int i = 0; i <= 2; i++)
        {
            if (filetype == acceptedFileTypes[i])
            {
                //accept the file, yay!
                acceptFile = true;
            }
            }

I have aI have a RadUpload

[Rumen]

Hi Pedro,

You can validate the image dimensions by converting the InputStream of the uploaded file into a Bitmap and check its Height and Width properties in the FileUploaded event handler. Here is a sample implementation of the described approach:

<telerik:RadAsyncUpload RenderMode="Lightweight" ID="RadAsyncUpload1"
    OnFileUploaded="RadAsyncUpload1_FileUploaded" PostbackTriggers="Button1"
    runat="server">
</telerik:RadAsyncUpload>
<asp:Button Text="Upload Images" ID="Button1" runat="server" />

Copy Code

protected void RadAsyncUpload1_FileUploaded(object sender, Telerik.Web.UI.FileUploadedEventArgs e)
{
    using (Bitmap originalImage = new Bitmap(e.File.InputStream))
    {
        var width = originalImage.Width;
        var height = originalImage.Height;
    }
}

Here are some resources you might also find useful:

• How to validate height and width of image uploaded using RadAsyncUpload
  
• Async Upload, fixed crop and resize image
  
• How to Persist Uploaded Files

• How to Reduce loaded image pixel size in RadAsyncUpload

Best regards,

Rumen
Telerik by Progress