To share an image of your POSU as a tweet, you will need to have the image saved to your computer or device, and a Twitter account. Here are the steps to share the image as a tweet:

1. Log in to your Twitter account.
2. Click the "Tweet" button to compose a new tweet.
3. Click the "Add photo" button to upload the image of the NFT from your computer or device.
4. Type a message to accompany the image in the text field.
5. Click "Tweet" to post the image and message to your timeline.

It's also possible to share the image of an NFT via a link. In this case, you will need the link to the NFT image on a marketplace or website and then you can paste it in the text field on your tweet.