Hello there SlowMotionFred,
Thanks for posting here on the Apple Support Communities! This is a place where other Apple users can submit questions or respond to others to help lend a hand.
We can certainly see the smaller than expected icons there on the right side of your Dock. Let's take a closer look as we do our best to provide some additional insight.
To get started, it looks like this may be an issue with the preference files that control the Dock on your Mac. To get started, does this keep happening even after adjusting the Dock in the System Preferences? Change Dock & Menu Bar preferences on Mac For example, try changing the size of the dock and toggling settings like "Automatically hide and show the Dock", "Minimize windows into application icon", "Show recent applications in Dock", "Magnification", etc.
As you toggle the settings, try restarting your Mac and test to see if the new Setting is properly saved as you test things again. If everything works just fine, you can set it back to how you had it originally.
We hope this helps get you pointed in the right direction.
Take care.
