You want to post a visual to Instagram and also want to share it on Twitter?
If you don’t want to post each manually with their custom caption/message for each platform, you have two ways to kill two platforms with one stone, in a manner of speaking:
How-To Post to Instagram and Twitter – create an IFTTT recipe to auto-post your Instagram post from your Twitter handle. You can set the recipes up to only auto-post if a specific hashtag is used on your Instagram post, or if you want to repost every single Instagram you publish. Just make sure your caption in Instagram is under 120 characters to the Twitter text isn’t cut off.
How-Not-To Post to Instagram and Twitter – click on the Twitter symbol on the Post screen in Instagram to send your Instagram post to Twitter once you publish. However, this method will not “natively” post your image/visual in your Tweet; instead, your followers will see the caption text and a link where they must click to see the visual you just shared.