Online presentation sharing services such as SlideShare allow you to upload an audio track alongside your slides. You need to make sure that the narrative is exactly in sync with the visuals.
I have seen (heard) examples where the audio presenter starts talking about data or concepts that are not present on the visual in front of you. As a result, the brain starts to wander off, looking for missing pieces of information on the slide.
When talking to a live audience in person, you can draw the attention from the visual back to you. An exact sync is less important, and it is easy to fit in a slide story. During a short web presentation with audio, your audience is using the narrative as an explanation of the slides. Make sure they are lined up.
Sometimes, when you are short in time, that might actually mean inserting a slide with some quick (very short) bullets (did I just write that?) or a short sentence to support your side story. Something like: "Case example: 22% cost savings"