Question: I would like to change the image next to the search box to a styled input button.

Do I need to create a new delegate control to do this? Can I do this with css, if so how?

This is the standard search UI  

![enter image description here](https://i.stack.imgur.com/bRp3m.jpg)

This is the desired css button look  

![enter image description here](https://i.stack.imgur.com/t59MW.jpg)

Answer: 
The image is rendered using an tag which you cannot modify using just CSS. You could either

* A - Use some jQuery to modify the HTML for the searchbox. You can target the srch-gosearchimg CSS class to modify the image tag and point it to another source image.
* B - Use a delegate control to replace the entire searchbox

My vote usually goes for option B since I don't like messing with a non-standardized HTML layout that jQuery uses. E.g. if a service pack is installed which changes the default searchbox then it'll blow your jquery out of the water. For option B you do need to have server access. For option A you do not since you can include jQuery using a content editor part or in the masterpage using SharePoint Designer.
You can either replace the `DelegateControl` (if you have farm access)

<http://msdn.microsoft.com/en-us/library/ms463169.aspx>

```
<asp:ContentPlaceHolder id="PlaceHolderSearchArea" runat="server">
    <SharePoint:DelegateControl runat="server" ControlId="SmallSearchInputBox" Version="4"/>
</asp:ContentPlaceHolder>

```

Or you can override the `PlaceHolderSearchArea` in your page layouts (if you can only have site access)