Learn English – “How to […]?” and “Where to […]?” Questions that are not questions. Is this defensible

The Chicago Manual of Style notes:

Many writers assume—wrongly—that a colon is always needed before a series or a list. [Section 6.67]

So dispense with the colon entirely:

Is this the one you meant?

• http://blah.com/somebody/blog/article/foobarbaz.gif

Alternatively:

Is this the one you meant: http://blah.com/somebody/blog/article/foobarbaz.gif ?

Or:

Do you have any of the symptoms below?

• Headache
• Nausea
• Dizziness

The suggestion by Gary's Student to use bullet points is a good one.

If the questions must appear inline for some reason, you can number them instead:

Before we can examine the implications of neuroscience for criminal law, we must address two more fundamental questions: 1) Why do we punish criminals at all? and 2) How severely should we punish them?

With a longer inline list (perhaps three or more questions), use semicolons to separate the items. For instance:

Before we can examine the implications of neuroscience for criminal law, we must address four more fundamental questions: 1) Why do we punish criminals at all?; 2) How severely should we punish them?; 3) To what extent must punishment emphasize rehabilitation?; and 4) Should the family circumstances of criminals be considered when sentencing?

The semicolons aren't necessary for clarification, but they encourage the reader to consider each point more thoroughly by slowing down their reading of the list.