What do you folks use as a general rule of thumb for flowing text around embedded images? I know everyone's got different preferences in addition to standard rules; is there any time when you will place an image in line with text (i.e., with no text flow on either side) instead of allowing text to flow on one side or the other?
Obviously there are times when you're going to want the image apart from the text flow for design purposes. The examples I've run into recently involve laying out HTML newsletters (which are fairly narrow - less than 600 px so they fit into the crappy little window Outlook give you, and then it's split further into a 2/3 + 1/3 vertical arrangement) and a brochure laid out with similar narrow vertical columns. With a vertical area this narrow it's sometimes difficult to get recognizable images (none are larger than 250 px wide) and text without it looking like you're getting "crumbs" of text.
Addendum: I know there are, in fact, times when you'd want the opposite - if I were laying out one of E.E. Cummings' poems alongside a series of images, for instance, I would probably have zero issues with fragments of text alongside images since that could create a different flow / feel. This question doesn't have to do with that - I'm looking for other folks' preferences with more vanilla layout - magazine layouts with large images, web pages with narrow columns, etc.