Hey johnlaunstein!
The filename when hovering is the title of your image, if you edit your images in the Media library and remove the title it should not show up.
I’m a bit unsure what you mean about the captions, could you provide us with screenshots highlighting the issue please?
Best regards,
Rikard
I just had this issue and
found good solution on WP.org forum
https://wordpress.org/support/topic/how-to-remove-image-title-when-hovering-over-image
Add to footer.php before </body>:
<script type=”text/javascript”>
jQuery(‘document’).ready(function($){
$(‘[title]’).removeAttr(‘title’);
});
</script>