I appreciate that you have let us know which theme you are using as that is very helpful! Looking into the Pipeline theme, I noticed that this is a third-party theme that is designed and supported by Groupthought. Since this theme was not directly developed by Shopify, we are a bit unfamiliar with the style of coding that is being used. With that being said, It would be best to direct this inquiry to the developers of the theme as they would be in the best position to provide further support and insight to adding text when hovering over an image.