It depends on what you are using it for really. Obviously if you supply a product or service that you can take pictures of, then at least some of your marketing should be images of your own products and services, but interspersing that with stock photography is absolutely fine.
The key thing to think about here is – are you sourcing high quality, royalty free imagery?
You must not ‘grab’ images from Google or elsewhere on the internet and just use them without the consent of the image owner.
It also does not give a professional reflection of your business if the images you use are low quality, fuzzy or poorly considered.
So, stock photography – yes, but tread carefully!