CainIV - 11:18 pm on Oct 26, 2010 (gmt 0)

Often image ads can complete the overall backlink profile and maintain 'diversity normalcy' in the profile, even if the net effect is not as sharp, or direct, from the link.

Therefore, I think it is important to have image backlinks, as a particular percentage of backlinks, regardless of whether a text link in the same scenario would present the better advantage, in order to round off the build.