tst, and others -
First, the reason we don't automatically display attachments as images in the posts is because there are several attachment file type (vi, llb, etc) that cannot be rendered as images and they end up looking like the little red X. The system currently can only either render all attachments as images or no attachments as images. We don't get to pick which file types should use what behavior. I will put this on the wish list though.
Second point is a word of caution on the numbering scheme. The way the forums currently work is that the message numbers count up sequentially within the board. Because tst posted several messages in a row and no one else posted to any other threads in the Feedback board in the meantime, he saw the message id number increment. However, if you hover over the Reply # of # links you will see that the message numbers in a particular thread do not always increment in exact numerical order.
11-446
12-447
13-561
14-563
15-564...
Hope that helps,
Molly K.
Web Support & Operations Manager
National Instruments