There are some excellent companies out there that can provide a broad range of site audits for you. Moz has compiled and excellent list here: http://a-moz.groupbuyseo.org/community/recommended

Because they weren't on the list and I have a tremendous amount of respect for the knowledge and experience this company has under one roof I'd also mention Rimm-Kaufman (RKG)

Prices can vary wildly, ranging from free audits to audits that are $10,000 or more, so it's important to consider where your company is and what's needed and take it from there. Here's a great post on site audits from the RKG blog:

Building a Better SEO Site Audit

Hope that's helpful info. Also, if you've got someone savvy on your team, and you have more time than you have money, here's great site audit template (given as part of Annie Cushing's presentation at Search Love Boston in 2012)  that can really go pretty deep and help you construct one on your own:

http://www.seerinteractive.com/blog/craziest-internet-marketing-audit-checklist-on-the-interwebz

It includes links to an already formatted GoogleDoc that templates everything you need. Brilliant.

If the images are no longer on the site it's perfectly acceptable to let them 404. Those 404s aren't going to hurt you. They should eventually drop out of Google's Index, although GWT can have a very long memory and hold on to 404 errors for what seems like forever.

If you think there is value for your end user in redirecting to a relevant image on the current site, that's fine too. I just wouldn't let your motivation be fear that 404 errors are somehow hurting you. If the 404s are resulting because the content has been removed, this is a perfectly acceptable reason to have a 404.

Hope that helps!

Dana

Great question! Google Adwords Keyword Planner doesn't make the place where you can do this very obvious or easy to find. Here's where you can do what you need to do:

1. Log in to Keyword Planner

2. Click "Get Search Volume for a List of Keywords"

3. Upload your keyword list via the resulting popout screen

4. Run the report

5. In the subsequent screen, upper right, just below the chart is a link that says "Download Ideas" - Click that

Then you will have all the data in Excel, provided you are running something newer than Excel 2003 which I believe had limited capabilities (45,000 rows maybe?)

Does that answer your question or was I way off  Let me know. Hope it helps!

I really like Chad's last comment. Yes, if they start talking about "proprietary" software and intellectual property, they are probably full of beans. If you aren't going to own your data after you leave them, or if they won't give you 100% transparency into their methods and which keywords they are going after, then the aren't worth pursuing.

Hire someone who acknowledges that SEO is a matter of time, patience and intelligent work...not magic potions, spells and chanting.

Best of luck to you!