Google Webmaster - Dealing with 404s

I recently moved a website from html to php. For all of the important pages I applied 301s, however there are a lot of pages left I really dont care about.

These pages have started showing up in Google webmaster central. I was going to 301 them all but wonder is there a limit to what's a healthy number of 301s to have on a website.

Since this is only a 50-100 page site now, this would mean about 50 urls are being redirected.

I would prefer to just tell Google they don't exist anymore and have them remove from the serps, if that makes sense. Is there any way to do this?

Personally I don't think it will harm you at all if you just let it be and let nature take its course. Thats probably what I would do.

But then again it won't hurt to 301 all back to the homepage just in case there were links built to the page and you don't want to waste links.

If there are no incoming links though I'd just forget about it.

there are no incoming links. Most of these pages were individual pages that each contained a photograph and were linked to from a gallery. I've now changed the way the gallery works so it doesn't need all of these individual pages and since I don't try for traffic from images I don't really care about them.

Then I would just not worry about it.

Dealing with 301's is important for large sites that have backlinks to those pages or a ton of traffic that is landing on those pages. It's not so important for a site like yours from what you said.