This should be a really simple thing, but does seem to be. I wanted to use an icon for my search button. In the module I set “Use an Image” to yes, but this did nothing. My first search lead me to this page.
https://forum.joomla.org/viewtopic.php?t=282140
This did not work for me.
This page finally got me closer to what I needed; however, I really don’t like using a .gif file. The format is not as smooth as other formats.
https://forum.joomla.org/viewtopic.php?t=728841
I am using Gantry 5 Hydrogen theme and simply adding the “searchButton.gif” to the “/g5_hydrogen/images” folder got things working quickly.
I hope this helps someone else out there….
