I have said several times that slide decks should include more images and fewer words. If you make an image-heavy presentation it will have more impact on your audience than a wall of text.
However, the images you use need to be good ones, both in terms of their relevance and their quality. Images look best if they fill the slide. Crappy, low resolution clip art is not going to give you the professional look you need. Even worse, is using stock photos that are watermarked with the stock library’s name. It’s a giveaway that you don’t have the right to use the image. That’s a bad look for a professional.
Some organisations have official access to stock photo libraries. If yours does then by all means use it.
If your organisation doesn’t subscribe to a library, don’t worry. There are lots of website where you can get royalty-free, high quality, high resolution images.
Some websites you could use are:
One more point. When choosing your images try to find ones that fit your narrative but are not cliches. There’s more to accounting than using a calculator and there should be more than images of calculators in your slides.