There is nothing wrong with telling people to e-mail you for pics, however, IMO, those should be additional pics. Having 2-3 good pics in the ad gives the interested party the ability to see what they are inquiring about before actually contacting you.
Alot of people see that there are no pics with the ad, and decide that if the seller didn't want to take the time to post pics, why should they bother looking into it? This is not how I look at ads, (I know there are some people who are not sure how to add pictures to a listing, which is understandable) but I am just saying that there are many people who read the description and think to themselves, "wow that sounds like too much work for me" and never think about your ad twice. If there are some pics of the car, for example, a pic of the frame you have redone, and a good pic or two that shows the condition of the body, they might see that and think "that doesn't look so bad, I bet I could handle that work." I believe that if you have the ability to post pics on an ad, you should definitely do so.
I guess what I am trying to say is that I agree with TRANNY SMOKE, and having a few pics in your ad may make more of a difference than you think.
Just my two cents...