I don't have an answer to the thumbnail decision, but I did not use it when posting the meal and menu photos from my AA flights as well as the photos I posted in the "AA- Views Over the Wing [AA in flight photos]" thread.

I also prefer to see the menus and meals in a flow and since I am one of those who often posts 5-10. I agree with you and I would not click through the thumbnails.

On a separate note, I've been using Postimage.org for more than a year as I prefer it to other hosting sites. Oddly, they have had some recent technical issues where I could not even upload and today their site is offline. Not sure what is going on there.