I created a demo of this on my web site, where another user asked the same question. https://www.nomadcoder.com/thumbnail-grid-demo/
In your Custom CSS, enter the code below: Some themes have this feature built in. If not, you may need a plugin. I use Simple Custom CSS. Search for this in the WordPress Plugins.
Cut and paste below:
/*Display more title*/
.postimage-title a
{
white-space: pre-wrap!important; /* css-3 */
white-space: -moz-pre-wrap!important; /* Mozilla, since 1999 */
white-space: -pre-wrap!important; /* Opera 4-6 */
white-space: -o-pre-wrap!important; /* Opera 7 */
word-wrap: break-word!important; /* Internet Explorer 5.5+ */
}
End Cut and Paste above
Similarly in your Custom CSS plugin,
You might want to give your title a fixed height. This will keep the thumbnails wrapping correctly. If you check the link on my web page, you will see that they are NOT wrapping correctly. You may have to adjust the height until it fits your needs.
.postimage-title
{
height: 30px;
}
To change the font, add this line with the desired font size to the .postimage-title a section that you cut and paste above code above. Obviously, you should change ‘whatever’ to the desired font size.
font-size:whatever!important;