Blocking images folder from spiders

Good or bad idea?

[twist]

All the jpg images on my website are in a single folder. If I block this folder will the bots still be able to view the photos on webpages?

For example, would my images not show up on google image search if I block the images folder from spiders or will they still show up because of the references to them on the webpages?

I see no reason a spider needs to read through my image index when it can find all relevant images through links in the html. I am confused on the whole issue.

[Conard]

First, spiders do not "see" images as they crawl or index. They see code. If you block the image directory your images should also drop out of the image search index.

Some people name their images with keywords so they do show up on an image search thinking it will bring people to their sites. I see traffic from the searches but it doesn't convert to sales just stolen images:)