Vectors and photos in one learning module.

Mixing photorealistic and illustrated images can be tricky, but I think there are a few ways you could try to make it work. You'd have to be very careful and purposeful in your use of  these image types, though, to avoid an amateurish, hodge-podge clip-art look.

One strategy that might work is to treat foregrounds and backgrounds differently. Herge, the creator of the Tin Tin comics, is famous for his "clear line" style in which the backgrounds are detailed but the characters are drawn more simply. You might be able to achieve something similar by using photos as backgrounds and illustrated characters in the foreground.

Another approach is to stratify the image types into a "hierarchy of realities." It can work if a photographic character points to a flyer or infographic that is in an illustrational style, because the illustration is "less" real than the photograph; but I've found that it seldom works the other way--that is, if you try to have an illustrated character point to a photographic image, the "higher" level of reality in the photo makes the illustrated character seem less real. In other words, the photo makes it harder for us to suspend our disbelief in the reality of the illustrated character. So mixing image types can work if you adhere to a strict hierarchy of realities, in which your main characters and environments are the most real (not necessarily photorealistic, but just the most detailed and realistic compared to other images in your course). If those characters then watch a "video", it could be animated with less realistic imagery, because the lower level of realism makes your main characters and environments the most real things on the page. Within that "video", if the less-real characters look at a diagram, it could contain images that are even more iconic and less realistic, preserving the hierarchy of reality in which each embedded level is less realistic than the one above it.

Scott McCloud, the author of Understanding Comics, made the observation that as images become more abstract (less realistic), they represent specific people and object less, and start to represent kinds of people and objects more. So, following that idea, another way to mix image types would be to segregate them by what they represent. If you're going to have named characters have a conversation, those images will be representing specific people and could be on the more-realistic end of the spectrum. In the same course, if you need to animate some imagery to accompany a voice-over narration about customers, "customers" is a class of people, so in that situation it could work to use a group of 3 people icons. In this way, you'd segment your use of realistic and iconic imagery by whether the images represent specific people and objects or classes of people and objects. Same thing for objects: are you talking about TVs generally (the class of all "TVs") or are you talking instead about a specific make and model from a given manufacturer?

But most of the time, I think it works best to choose either an illustrated style or a photographic style, and not mix the two. There are a lot of ways to mess up when mixing these, and only a few ways  to make the mix work convincingly.

At least, that's my take on it.

Cheers!

    -Ray

Thanks Ray!

That was a really detailed answer! I honestly did not think from this perspective. 

My concern was using a photo on the opening slide, and vectors furhter on, on the next slides. You opened the whole new dimension in my question!

Gone thinking...

Halyna