Hi I am a new contributor and I want to know if I can upload my pictures to another site.
Yes, the images that are accepted by Adobe Stock and not exclusive to Adobe and can be uploaded to other stock sites.
Hi @Milagros5FCE and welcome to the world of stock.
As a contributor, you are providing non-exclusive content that you can use commercially and non-commercially for your needs including social media. This includes also that you can upload and offer the same assets to different competing stock media companies as long as they don't claim exclusive right on your assets. It is indeed not uncommon to find the same assets on different stock media and I can tell, from my experience, that assets that sell here may not sell elsewhere and vice versa.
I wish you good luck and many sales.