I've used thumbnails dozens of times. Some of the explanations talked about low-bandwidth users taking exception to multiple large pics. To me thumbnails provide an overview of the bike for very little bandwidth and let interested CListers get high resolution detailed pics. I think the details let possible buyers see the real value of the bikes I sell, how clean they are, the new or like-new components, the shiny bits. I sometimes spend a couple hours polishing the alloy, the rims, and each individual spoke. My pics show the components in a way that let's you see the name, the model, and hopefully answers questions that might make my bike the one sold.