Hi sampp18,
I have created sample that full fill your requirement.
HTML
<div>
<table>
<tr>
<td>
<asp:TextBox ID="txtImage" runat="server"></asp:TextBox>
</td>
<td>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
</td>
</tr>
</table>
<div>
<asp:Image ID="img" runat="server" Visible="false" />
</div>
</div>
Code
VB
Protected Sub Button1_Click(sender As Object, e As EventArgs)
img.ImageUrl = String.Format("Images/{0}.jpg", txtImage.Text.Trim())
img.Visible = True
End Sub
C#
protected void Button1_Click(object sender, EventArgs e)
{
img.ImageUrl = string.Format("Images/{0}.jpg", txtImage.Text.Trim());
img.Visible = true;
}
Screenshot