Images not seen on here by others !

While there might be a small number of people blocking image display, the main reason for the difference is browser caching.

vBulletin attachments are served the same way static images are served, meaning they can be cached by the browser. If you already have an attachment in a thread cached locally, when you return to the thread, you will not download that attachment again. As such, you will not increment the attachment view count either.

Calls to display a thread page however do not use cache for the main thread body content. So, every call you make to "showthread" will increment the thread view count.