File this under "I never thought I'd see the day," then revamp your thinking and refile under "I always knew this day was coming."

Google has introduced image ads. In a two-fisted upgrade of both AdWords and AdSense, image ads will be optionally displayed on content sites through the Google advertising network—which is to say, AdSense and AdSense Premium sites. Whose option?— you might ask. Everyone's option, is the answer:

• The content site must opt in to possible displays of image ads. (The option has not been placed in the AdSense account pages as of this writing.)

• The AdWords advertiser must opt in to distribution of ads (text and image) in the content network.

• Finally, Google must determine that the advertiser's image ad is more relevant (or more appropriate in some undetermined way) than the same advertiser's traditional text ad. Google is not disclosing how it chooses between displaying a text ad and an image ad; I am pressing my Google contacts for answers and will blog any useful results of those conversations.

As to the ads themselves, advertisers have a choice of four banner configurations, the largest of which contains 728 horizontal pixels. Graphics must be relevant to the keywords associated with the ad. Descriptive text embedded in the graphic is recommended but not required. Animations are not allowed.

The image ad program will probably be slow to take off, for a few reasons. AdWords advertisers are not ramped up to produce banners. Some AdWords users avoid distributing through the content network. AdSense customers might not wish to opt in to the program, preferring to keep their ad displays in the text realm—historically one of the selling points of AdSense participation and effectiveness.

Is Google playing with fire? Not really. Google might be playing with an unsuccessful program, but I don't see the company or its integrity as an advertising syndicator becoming damaged through the distribution of marketing images.