Round numbers: 0.5m per pixel at 300dpi is 150m per inch so a 1km box is 7 inches by 7 inches. My city website has aerial survey data that looks to be much high

Round numbers: 0.5m per pixel at 300dpi is 150m per inch so a 1km box is 7 inches by 7 inches. My city website has aerial survey data that looks to be much higher resolution data so you could also try there.