Google Slides – How to Add Transparency to Background Image

This is currently not a Google Docs feature (and not possible) based on online documentation and no better answer. Apparently, this worked at one point in Google Docs, but it required viewers to use Google Talk (and this combination was buggy at the time).

An alternative I went with is PowerPoint 2010, which comes with a feature to broadcast slideshows to users over the Internet.

Google Docs Presentation only has a very limited set of image options ranging only to resizing, rotating, and moving. Any additional image manipulation must be done with other software. Many options are available in this area, from free to big dollars, such as Paint.NET and GIMP up to major programs such as Photoshop. Each of these editors have their own advantages and disadvantages depending on what exactly you need to do. If you only need to do basic cropping then you can use Paint on Windows or Paintbrush on Mac which both come free with your OS.