No, NetSocial does not resize images for social media platforms. The user will need customize the post for each social media platform under "Select Socials to Customize" and add a different image if they want it tailored.
NetSocial does convert images to JPG for Instagram because Instagram only takes JPGs.
Under "Add Media", you can see media size recommendations for 3rd party APIs.
If you have any questions, please reach out to Success at firstname.lastname@example.org.