I have a site that is simply a search box to search a cloud-hosted database of .tiff images, and then all of my content can only be accessed by entering a search term. So for example, you're on the home page www.example.com and you type in "search" to the box and hit submit. Then it takes you to www.example.com/?q=search, which is a page of all my .tiff images with "search" in the description. How can I get a page like www.example.com/?q=search indexed, WITHOUT making a humungous list of search terms that people might type in?? I know about mod_rewrite, but it seems like for that you need to know ahead of time which URLs you'll need to convert, which I don't. All of these pages will be dynamically user-generated by typing into the search field. Please help!
Google has stated they do not want to index search results from other sites (IE their search results leading someone else's search results is considered poor customer experience) so you'll have an uphill battle to get them indexed and ranked.
Beyond that what you'll need to do is get some links from your home page to some of the search results, as you mentioned you want it to be fully automated so I'd suggest a "recent searches" box on the home page that has links to the results pages for the last 10 or 20 searches.
Once you get Google into some of the interior pages you'll want to make sure they go further then just the one page, you may want to include "related searches" on the actual results pages and or a tagging/category box on the image pages themselves (near the description).
It could also help to put a handful of "navigational" links near the search box that users will find useful IE a static link to "trending searches" "all time most popular" "popular tags/categories" etc. All of these can be generated on the fly based on search query data you collect, and will allow Google to start indexing and exploring your internal pages.
Building useful tools on the data that people will like and link too (think Google trends) will also get links for pages that can be "hubs" and link to many interior pages.
What about creating static / SEO friendly pages such as
www.example.com/someothersearch and have those pages display images from that search results.
Now with search friendly URL's you can generate an XML sitemap and submit it to Google/Bing
I would also create an XML Image sitemap file.
Since your site is all images you should also integrate with pinterest button
Just another thought you could gather all the search phrases from your database and generate and XML sitemap with the dynamic URL's. You're allowed up to 50k URLs per sitemap