Image-based logos feature an image. Now where icon leaves off and image begins can be tricky to define, but here are some examples of what I would consider image based logos.
"Busy Having Fun" was a potential client that emailed over the internet saying they had seen a graphic on my website that they liked and would be interested in getting a design like that. That design is represented by the first two on the right hand side. This was for a company they were starting in Australia that rented watersports gear.
After the first two designs I went a little crazy and the result was this group of design. Many of them have images in textures and silouhettes and so fall under the image-based logos concept.