vb 获取网络图片宽与高并修改宽与高在ASP：Image控件中显示修改后的图片

在VB.NET中获取网络图片的宽度和高度，并根据需要调整尺寸后再显示在ASP.NET的`Image`控件中，可以按照以下步骤进行：

1. 首先，你需要使用`System.Net.WebClient`或者`System.Net.Http`等库下载图片文件。假设我们使用`WebClient`:

Imports System.IO
Imports System.Net

Public Function GetImageInfo(url As String) As ImageInfo
    Using client As New WebClient()
        Dim bytes As Byte() = client.DownloadData(url)
        Return New ImageInfo With {
            .Width = If(bytes.Length > 0, Image.FromStream(New MemoryStream(bytes)).Width, 0),
            .Height = If(bytes.Length > 0, Image.FromStream(New MemoryStream(bytes)).Height, 0)
        }
    End Using
End Function

Private Class ImageInfo
    Public Property Width As Integer
    Public Property Height As Integer
End Class

在这个例子中，`GetImageInfo` 函数下载指定URL的图片数据，然后通过`Image.FromStream`获取其宽度和高度。

2. 然后，你可以根据需求缩放图片。这里以保持长宽比为例：

Function ResizeImage(url As String, newWidth As Integer, newHeight As Integer) As Image
    Dim info = GetImageInfo(url)
    Dim ratioX = newWidth / info.Width
    Dim ratioY = newHeight / info.Height
    Dim resizeRatio As Single = If(ratioX < ratioY, ratioX, ratioY)

    Using client As New WebClient()
        Dim bytes = client.DownloadData(url)
        Dim resizedBytes As Byte()
        Using memoryStream = New MemoryStream(bytes)
            Using image = Image.FromStream(memoryStream)
                Dim newSize As SizeF = New SizeF(newWidth, newHeight)
                Dim newSizeAsInt As Size = New Size((image.Width * resizeRatio).Ceiling, (image.Height * resizeRatio).Ceiling)
                Dim graphics = Graphics.FromImage(image)
                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic
                graphics.DrawImage(image, 0, 0, newSizeAsInt.Width, newSizeAsInt.Height)
                resizedBytes = New Bitmap(graphics, newSize).ToByteArray()
            End Using
        End Using
        Return Image.FromStream(New MemoryStream(resizedBytes))
    End Using
End Function

' 使用方法：
Dim modifiedImage = ResizeImage("yourImageUrl", NewWidth, NewHeight)
ImageControl.ImageUrl = "~/YourPath/" & "modifiedImage.png" ' 将图片赋值给Image控件

这会下载图片，根据新的宽度和高度比例缩放图片，然后返回一个新大小的`Image`对象。