I assume you run Mac software:
Go to the App-store and search for "AutoResize"
A free and simple application for reducing mbs of fotos. Install the free version and you can alter the pictures as requird. The app produces a reduced copy so the original does not get affected.
Does the job for me.


Hannes
once: Green M3W; 2013
now: Red 4/4 Sport; 2011
and some practical cars for use in real life