Ok after some more research, I found a solution.
first I saw someone had added a couple of functions to the Adafruit GFX library which uses RAM instead of flash memory. Apparently, it worked for them but didn't for me.
What ended up working for me is a library called OLED_Display_SSD1306 by AbdulBasitKhatri. It uses RAM so I only get 32X32 pixels at a time. I'll have to position 8 little images in order to fill my 64X128 pixel display. Not ideal, but at least I can store a bunch on an external EEPROM now.