Hi merve,
Please use below code and modify as per your requirement.
HTML
<div id="div1" visible='<%#(Eval("ResimYolu")).ToString()!=""? true:false %>' runat="server">
<img id="imgResim1" src="../path/<%#Eval("ResimYolu") %>" style="width: 75%" alt="<%#Eval("ResimAdi") %>"
class="w3-margin-bottom" />
</div>