You can find photos of many of the S Gauge K-line cars at http://aftrainmaster.com/
The K-Line boxcars have their own link http://aftrainmaster.com/priva...simagesbox_kline.htm while the tank cars, cabooses, and hoppers are listed in their respective categories under subsection "Other Manufacturers".
Portlines also has pictures of some of the K-Line cars. One is definitely a photo, the others may be drawings or clipped from photos. http://www.portlines.com/K_LINE.htm
I have two of the K-Line boxcars and they are slightly bigger than Flyer or S-Helper boxcars. They have excellent wheel sets. AF Train Master has a nice page about the size range of S Gauge cars http://aftrainmaster.com/private/gauge.htm
Craig