I agree with some of the other posts on this thread that you may use 'other' pictures (not your own) to get the idea across to the customer. If done without pirating, it is simply marketing.
HOWEVER, I'll bet that most on here who have at least one truck running full-time, will agree that you'll regularly have at one or two real-life opportunities a week to photo your own work and come up with some really great before & after pics.
So shoot some of your own. You're the guy who gets more x-mas cards from his custys than any cleaner alive, so they should be ecstatic about their home being featured in your website.
Come-on, certainly all of your jobs aren't high-end (non-trashed) carpet. And even if they were, why would you want to post killer before/after pics, when thats not who your customer base is in the 1st place?
You're marketing transmission overhauls to Lexus drivers then?
You should take a pic of yourself bathing in the waste water as it blasts out of your exhaust. Thats what we did & it tripled the hits to our site.
Ok we dont really have a site but hope to have it up this month & we intend on using a mix of both 'other' pics, and of our own. The housewife/pet/kid pics will most likely be the 'others' and we will photograph our own before/after.
Good luck & can't wait to see your site once it's built.