inception_v3 expects a color image (3 channels).
The error message seems to be a bit strange and should be:
RuntimeError: Given groups=1, weight of size [32, 3, 3, 3], expected input[10, 1, 299, 299] to have 3 channels, but got 1 channels instead

Did you modify the architecture somehow?
Anyway, try to repeat your single channel image or cast it directly to RGB after loading:
image = Image.open(PATH).convert('RGB')