When I use the thumbnail feature a comment is automatically inserted. Example <!-- MSComment="autothumbnail" xthumbnail-orig-image="file:///C:/Data/Webs/ValveChatter/diamondjubilee/emeritus_awards/127.jpg" -->

Is there a way to suppress this comment? I know how the thumbnail got there and I like to keep my code uncluttered.

You cannot suppress the generation of the comment, it is part of the auto thumbnail generation and tracking info. You shold be able to delete the comment after you have saved the page so all your thumbnails are saved to your current web.

I've been doing that.

Hmmm.... Seems like the suppression feature would be nice to add to Expression Web.

I have a page with 172 thumbnails, I guess I'll leave the comments :-)
 

Have you tried running the optimize html tool? If you are uising a DWT make sure that you select only the comment types you wish to remove and test on a back-up first.