As soon as I discovered that I would have to run a script to convert .xbm files to an array that would be usable by SSD1306, I decided that I would write a simple python application to import .xbm files, draw new ones, and export the display data to an array with VHDL syntax. It took a while to get the GUI to work how I wanted, but eventually the app worked:

Screenshot:

Python code is uploading to Github