upload only gif/jpg/bmp images

how to validate the image type in vb.net?

i want to restrict to the user to upload only gif/jpg/bmp images

what is the best way to restrict?

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service2001Author Commented:
i need the code to pupup alert message that, you are allowed to upload gif/jpg images.

is there any code can do that?
You can display a javascript alert message when the user clicks on a button to upload the image.

<input type="submit" name="Button1" value="Button" id="Button1"  onclick="javascript:alert('you are allowed to upload gif/jpg images.');" />

Now in your button click handler on the server, simply validate the extension of the file using the fileinfo classe's "Extension" property
service2001Author Commented:
can i have a complete code please?
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You can also use System.IO.Path Class in .NET

string fileName = @"C:\mydir.old\myfile.ext";
string extension;

extension = Path.GetExtension(fileName);
service2001Author Commented:
but how do i check on client side?

service2001Author Commented:
if you have done similar, would you paste the code here for my reference? thank you!
<TD align="right">
<asp:label id="lblUploadLogo" runat="server"></asp:label>
<TD colSpan="2">
<INPUT id="fileupload1" style="WIDTH: 299px; HEIGHT: 22px" type="file" size="30" name="fileupload1"

<asp:image id="imgLogoFile" runat="server" Width="30px" Height="24px"></asp:image>
<asp:RegularExpressionValidator id="Regularexpressionvalidator1" runat="server" ErrorMessage="Select valid file *.gif or *.jpg or bmp file!"

ControlToValidate="fileupload1" ValidationExpression="^(([a-zA-Z]:)|(\\{2}\w+)\$?)(\\(\w[\w].*))+(.gif|.bmp|.jpg)$"></asp:RegularExpressionValidator></TD>

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