I had post a way before to control the images that are posted on your page, the only thing was that element effected all images on your page. Now I have the answer to that problem.
I have spent a little more time going over the CSS for CherryTAP and if you enter the following code into your skin you will be able to force any images in your comments to display at the size you want ie: 400px by 600px or 400x400 (what I use). This will also help to increase the load time for your page because your browser will not have to load enormous images.
Here is what you need:
table.user_comment_body img {
max-width:400px;
max-height:400px;
}
Just drop that in your skin and if you wish change the pixel size to suit your needs.