There is actually a setting if you right click on your project name (default WindowsGame 1) in the solution explorer that lets you select "compress content pipeline output files". The project name is the one directly under the solution name, and will most likely be the second listing in the solution explorer. Once you have selected the project name, right click, and hit "Properties". That should bring up a page with some selections on the left hand side. The fourth one down is "Content Build*", and if you select that, you will see the option for compressing the output files.

I did a test on a game I recently built, and in the final install package, the size was reduced from 12.1 mb to 3.31 mb! So it does make quite a bit of difference in the hard drive footprint.

As a side note, when XNA produces the XNB files, they are composed of raw data which is the reason they are so huge! Hope that helps, and if you have any trouble finding the compression setting, feel free to pop into the chat room and one of us would be happy to walk you through it!

I've successfully followed you tutorials with the goal of replacing OpenTK with Monogame for my application.

However, I've noticed that the .xnb files which the XNA Content project generates are huge in comparison to the original .png files (sometimes more then 10x the original size!). So far, I've been unable to figure out how to, f.e. add compression options or how to reduce the colordepth of the textures, in order to reduce the size somewhat.

In your method, is it possible to apply some form of compression or alter the properties of the generated XNB's in any other way?

Thank you.