We take stock photography and overlay a quote or factoid for social media posts. We usually use a filter or coloured overlay as well.
Can we place our logo and/or website URL on this image?
Really depends upon the license for the image.
In many cases it would be fine.
However, if the image contains people, there are some licenses which state people can't appear to be endorsing anything.... which means then it comes down to your usage.
This really can't be answered definitely. You need to check the license for whatever stock site you are purchasing images from.