Image classification has high error rate

Hi everyone,
I’ve been trying to train a model to predict building age from images scraped from Wikipedia and despite what I’ve tried, it doesn’t perform very well.
Might someone take a quick look at my code to see if there’s anything obvious you’d recommend trying to improve the accuracy?
What I’ve tried:

  • Different ways of problem structuring e.g. image regression vs. century bucket classification
  • Multiple models
  • Multiple image sizes
  • Multiple image resizing methods
  • Multiple learning rates
  • Manually removing problematic images
    Thanks very much in advance!
    link to Colab