Searchable Image Gallery

Evidently, your images don't  contain any metadata either. 

online metadata and exif viewer

You could use Bridge to add keywords and other metadata to your images.

https://industrydev.com/adding-metadata-to-photos-using-templates-in-adobe-bridge/

Later on,  export image metadata to a text or CSV file.

Exporting Bridge metadata to Excel or CSV

Theres no real simple way for thousands of images, you have to implement some organisation initially. That means storing your image details in a database where you would also store keywords associated with the images. A user would then enter a keyword in the search form field on your website page and return any image which has that keyword associated with it.

You could also store the images as a category in the database and have a drop down menu on your website page from which the user could choose from the available categories.

Much smaller galleries could be accomplished without a database by using jquery to select them by a data-category name which you would incliude as part of the images src attributes  but if you have dozens of images associated with a data-category you would want to split the returned results over several pages not just dump the whole lot on a single page. Do a google search for - jquery searchable image gallery for simple examples with limited images.

The initial organisation of the images and how you want the search to work is the time consuming and thought provoking part of the exercise. Getting the correct results from a database or jquery solution is a few minutes work.

At the moment it looks like you are manually creating pages for your gallery and numbering them from 1-11, which if this is the case its not an efficient way of managing large amounts of data.

This example was made using Wappler Basic. Because this version does not include database options, a JSON dataset has been used. A JSON dataset can be created from your MySQL database​.

The example can also be created in Dreamweaver using the following extensions

• App Connect
• App Connect Data Traversal
• App Connect Animate CSS
• App Connect Masonry
• App Connect JSON Data Source