If I use the “Straight Dope” style from the Quick Style Chooser box, I don’t see the regular icons - reply button, envelopes, etc - but only a square blue box with a question mark inside. Other styles - Standard, Bright Links, and Straight Dope Message Board VBulletin 3 style - don’t seem to have this problem.
What browser/operating system are you using?
If it’s Safari / Mac OS X, the blue question mark icon is what it displays when it can’t load an image for one reason or another. I’d venture to guess the SDMB server went down or otherwise had some problem when your browser was trying to get those specific images.
Damn, you’re good. It is Safari / Mac OS X. The problem remains, although it’s easily ignored by switching to another style, or by using Mac OS X Firebird / Firefox.