jpg directory into database - update live OR directory search w/ no database?

I have a folder of images on a server (all jpg files in the same directory) that I'd like to pull up based on user input. The files are saved as a string, let's say ABC_12345_GG.jpg... I was first planning to set up a directory search, not sure if that will work in this case though, it would need to be Dir (*<USERINPUT>*GG.jpg). First of all, would that work? how do I specify the userinput variable within the directory function and wildcards??

The other option would be to put these into a database (with a link to the file names). There are thousands of images that are created continuously however. I have no idea if it is possible to create a database that will update on the fly based on images coming into this directory... Is this the route to go?? If so, what type of database and how would I go about doing this??

Thanks much for any information you can provide to the newbie!