This website is a meta tool that combines all the available image tools in one website. You can upload an image file or provide an URL and you can directly for example use all the reverse image search engines available, this is a good feature to check for example, if an image was stolen, because in our copyright madness times you can already get in trouble for one image that you don't have the rights to use, of course most people today do not care, but for example if you do business, you should care, because you may encounter legal troubles and big fines.
The website also has a lot of other features like extracting metadata, as well as multiple ways to edit and re-host images, but I usually do those myself offline.
I usually use web tools only on images that are publicly available on the internet, so I just specifcy an URL, out of respect for privacy and copyright, since you never know where things end up. Some image operations like extracting meta data and some reverse image search engines with face recognition active also open up possibilities to stalk people, but to do that is not so nice, if you still want to do it, you can calm yourself by the fact, that big companies or online platforms do those things to stalk people by default, automated and a million times worse, since it is them who provide those features in the first place.
In short I rather keep ImgOps bookmarked instead of all those other websites individually.