[Plugin: ZenphotoPress] Image sizes for worpress posts smaller that original

First of all I would like to thank Simbul for this great plugin. This is exactly what I was looking for to use pictures from separate photogallery in WordPress posts.
All works great, but I have kind of problem/issue regarding way of usage. Image files in my Zenphoto gallery as a rule have a quite big size (1600×1200), though displayed in a gallery with smaller resolution surfer has ability to view full-size picture. At the same time, when I insert photo in WordPress post I do not want to insert thumbnail , but instead I wish to insert decent size picture (like 600×450) for example. It means that ZenphotoPress inserts full-size (1600×1200) picture in the post and makes it smaller just with width=600 height=450 . It makes page to load slowly because browser loads full-size picture which I do not need in the post.

Is there some kind of solution/hack to resolve this? It would be nice if ZhenphotoPress could resize image on the fly and make a separate low-res copy to insert in the post though I understand that it is a difficult task and not the native task for this graet plugin