One of the issues with posting infographics on social media is getting a good-looking preview that will often determine how many visitors you receive.
There can be a technical issue with posting infographics and other images as links - the preview or thumbnail that is shown might not be correct. It can be either outdated, or cropped incorrectly.
Now the good news - there is a way around it.
On Facebook, you can run your link through the Debugger Tool and check what the infographic looks like before you post. Here if you spot that the image is not updated to your latest one, click "Scrape again"
The same can be done for Twitter, with their Twitter Card Validator tool