There are two options for you:
1. Store the image also against the product itself as a BLOB data. BLOB is nothing but a representation of byte and the abbreviation is Binary Large Object and the filename for it, if necessary.
2. Second option would be to store the images on the file system and their filenames in the database against the product. When you what to show the image read the file name from the table and get the corresponding file from the file system. You should be storing the directory path of the stored files in the configuration file.
If I was you, I would opt for having the image in the file system only and not in the database. I am not a big fan of storing the BLOB data in the table.