Hi. You didn't mention the resolution or pixel size of the images you're using. If you're using a low resolution and the Presentation goes full-screen, you may be seeing the results of not having sufficient information in each image.
If you have the Creative Cloud, a method you may want to try would be to do it directly in Adobe Acrobat (DC, if you're working with a new version, or Pro for older versions. You can create a PDF from multiple images, tell it to be a presentation, tell it to automate, if you desire - so it'll be more of a slideshow.
But do make sure that if it's being viewed full-screen, that you have at least 1920X1080 pixels for a normal screen, and 3840 × 2160 for 4K (or retina).
Thank you so much for your detailed reply! That's very helpful!
I'm a bit new with this so I realize these are probably dumb questions, but does it matter what I export the file as? PDF, PDS or JPG?
I'm so glad you found that helpful!
What you ask is a really good question. Used to be, Adobe products didn't understand other Adobe products, but that changed a few years ago. So, Acrobat will understand PSD's really well. However, PSDs are often a pretty large file size. A high quality JPEG would keep your file sizes lower, and still look really great on a monitor in a presentation. So, I recommend JPEG, but really, if you want to skip a step, PSD'd work nicely.