Not sure how well this will work with the Galileo but the Arduino IDE defines sketch upload limits in its board.txt file. You can find the file at:
[ide location]\hardware\arduino\x86\boards.txt
You should see the following entry:
izmir_fd.upload.maximum_size=262144
This defines the sketch size limit of the Galileo board in the Arduino IDE. Modify as needed and reload the IDE for changes to take effect.