Uploading is the process of moving digital data files such as photo and documents from your computer or camera and placing them on social media. Copyright is the legal term to describe a persons ownership of their work. It included things as photos, music, artwork and writing. The person who creates the work is the copyright owner.
The law assumes that the person who creates the work is the author of the work and has the only legal right to publish and copy the work. An unauthorised copy of a piece of work placed on a website or on social media is to be a copy right infringement.
Copyright restrictions on uploading vary between media sites. The social medias terms and conditions may change the right to the owners work. Some social media sites gives them the right to copy and use original work without the owners permission. For example sites such as Facebook. You Tube, Google, Twitter gives itself the right to use anything that the original creator has uploaded or posted.
You need to read carefully the terms and conditions on the site you want to upload on before sharing your work. If you don't agree with the terms you have option is to choose another site that will let you share your work without limiting your rights.
If a person or organization breaks the law the owner of the works has the option to sue you for using and copying their work without permission.