Any idea why some members posted thumbnails appear and I can view them, while others don't appear?

If you can't see them most likely no one else can either. The link to the image isn't valid anymore, that's why you only see a X.

Any idea why some members posted thumbnails appear and I can view them, while others don't appear?
Same thing here

If you can't see them most likely no one else can either. The link to the image isn't valid anymore, that's why you only see a X

I thought the thumbnails are on the same server. For example, your sig. show the following
"The shallow end of the gene pool needs some chlorine!

Mods: 20% tint, Blaupunkt ME3 TV/DVD player wired into factory dvd wiring (read how to here) , 7" monitor (see it here), video on Navigation screen, reverse camera, Street Scene grille, hood, vent, and sunroof deflectors, and a fully functioning CAR-MADA-PUTER"

When I click on the (read how to) link I can not see the thumbnails you refering to in your excelent explanation.

If they want to cancell some thumbnails to save space, yours should always be there for other members to learn from your experience.

Btw I don't see an X either.