There are many things to consider when thinking about the relationship between type and image. You always want the relationship to establish congruence and opposition. Basically meaning harmony and contrast. Of course, never forget the importance of unity. Space is another factor that effects the relationship of image and type. The amount of space effects whether the image is directly correlated to the type and vice versa. Type and image have to work together to create interest for the viewer. The overall message should always be your main goal. How you use type and image effects the outcome of how well your message is communicated. The two have to establish a balance of congruence and opposition. There needs to be opposition to create interest. Merging type and images is key in creating a successful design.