Tools

ShareX: https://getsharex.com
API

To upload using curl or make a tool you can post using:
curl -i -F name=test.jpg -F file=@localfile.jpg https://uguu.se/api.php?d=upload (HTML Response)
curl -i -F name=test.jpg -F file=@localfile.jpg https://uguu.se/api.php?d=upload-tool (Plain text Response)