TO USE
1. Log in manually to all of the social media sites you want to post to in the same browser window using different tabs. *Required
2. Go to this page.
3. Enter the content in the form fields, and use the post buttons to publish.
4. Go to the auto-opened pages and check and post.
YOU NEED AN IMGUR CLIENT ID
This is so you don't have to upload your images to this blog, but still don't have to use URLs for images, which approach often fails in social media sites.
Go to imgur to set up an imgur client ID.
NO TO imgur
If you don't want to use imgur, there's a less powerful clipboard based version here which uses your local system's clipboard to store the image for you to paste into each target site.
NEXT VERSION
Update 1: Make the post action for each target SM site automatic too. This might take some time as it involves the use of each target platform's API.