Please see the code, I have made a slight change in usercontrol's ascx file only, do I need to upload its dll as well?

In a webuser control I had below line.

 <img src='<%=Users[0].URL%>' alt='<%=Users[0].Name%>' />

which I had modified by just adding an if condition as below

<% if(Users.Count !=0) { %>

 <img src='<%=Users[0].URL%>' alt='<%=Users[0].Name%>' />

<% } %>

Now my question is, will it do if I just upload usercontrol.ascx file to the server or I'll to upload its dll as well?

Since I did not modify its code behind page file, I do not think I need to do so. Please help me and let me know if I am wrong.