Possible to change the Search Engine? / Adding new feature to Image Pages.

Hello all. I am wondering if theres a way to add a Hidden Tag to each image page for the Search Engine. I have tried the vanilla search engine but I haven't been able to modify the image to do it. I would much rather make it a customized one.

Image Gallery has a Carnival, Admin will be allowed to add tags such as "Vacation, Carnival, Clowns, etc" and when searching for carn or carnival, This will show up as one.

Saving it per Image Page ( Using a DB Array in Data folder ) would be nice, but if I remove the file and place a new one, I would also like to know how to make a Admin Link to remove the image from the database ( or maybe a file size check? ) so I can replace it with a new one as needed. ( Delete the Cached Thumbs / Image / DB Registeration etc ).

I know this is much, but I tried a lot to get it this way with no luck. I am using a highly tuned gallery theme but I can edit it quickly. Any help or coding is highly welcomed.