The cache folder/hash for resized product images in Magento 2 is generated dynamically based on the image dimensions and aspect ratio, and it is stored in the cache_metadata table of the Magento database.
When an image is uploaded, Magento creates a unique identifier based on the image's size and aspect ratio, and uses that identifier to create the cache folder/hash in the pub/media/catalog/product/cache directory. The identifier is then stored in the cache_metadata table, along with the original image path and other metadata.
The cache_metadata table is used to map the cache folder/hash to the original image path, so that Magento can serve the cached image in place of the original image when the resized version is requested. This allows Magento to serve images quickly without having to resize them on-the-fly every time they are requested.
You can query the cache_metadata table to see the cache folder/hash values for your images. The SQL query would look something like this:
SELECT * FROM `cache_metadata` WHERE `media_type` = 'image' AND `metadata` LIKE '%/your/image/path.jpg';
This will return a row containing the cache folder/hash value for the specified image path.