I don't know guys if you know the answer to it but I have a question and I am going to ask it

As we are all fella stockers and we all have images in many different websites there are no better people to ask this.. Here it comes:
- Is it ok to sell our own images on our personal websites too?..
I mean I just want to sell my own images for much higher prices.. for example, a vector that costs $10 on iStock let's say, I would make it $20 and put it on my website.. I am a professional designer and did many shopping websites and just would like to use that advantage..
I have no intention to turn it into a stock community website or a site that asks other stockers to submit..
It is just personal..Would it be ok? Do you know if the current "big 6" would object this?
Big stockers in the business with 10.000 images are always asked the question "why they don't start their own stock website".. And they answer it would be risky, because they would need to withdraw all the images they have on SS, IS, etc.
This is nothing like that.. This is like a personal art selling website.. That's it..
What do you think?