Hide show image based on Database column value in ASP.Net

I also tried another example but still showing error code

 <asp:Image Visible='<%# (Eval("ImageName1") == null ||  Eval("ImageName1") == String.Empty) ? "false" :"true"%>' ID="Image4" runat="server" width="100px"
                ImageUrl='<%# Eval("ImageName1") %>' GenerateEmptyAlternateText="True"
                EnableViewState="False" /> 

error

 Compilation Error
Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.

Compiler Error Message: CS0030: Cannot convert type 'string' to 'bool'

Source Error:


Line 836:                            
Line 837:    
Line 838:                                      <asp:Image Visible='<%# (Eval("ImageName1") == null ||  Eval("ImageName1") == String.Empty) ? "false" :"true"%>' ID="Image4" runat="server" width="100px"
Line 839:                ImageUrl='<%# Eval("ImageName1") %>' GenerateEmptyAlternateText="True"
Line 840:                EnableViewState="False" />