Fix changing properties, scale images and other improvements

[dhaavi]

• Advertise that we may write icon pixmal/title/tooltip
• Set values as props.Properties.Set when setting
• Save properties to instance
• Improve logging and log messages
• Fix linter warnings
• Add support for auto-scaling images

[andydotxyz]

Thanks for this. In the future please don't force push once review has been done - just makes it a little harder to review ongoing.