The edges of the Buddha are somewhat jagged. I'm guessing you used the magic wand at the default setting. I tried it myself and the best way with the wand is a tolerance of 32, then select outside the statue and keep selecting till the silo is complete. Next adjust the refine edge feature which is now highlighted in the menu bar on top. Set radius 1.0, contrast 0, smooth 2, feather .05 and expand 2. Now hit delete. The edge should look smoother, experiment with the settings to see what's best for you.

If I remember rightly, I think I used the magnetic lasso which does kind of 'jump' to the edges - so a similar effect to the magic wand. But yes, I DO always forget to clean up my edges with masks and feathering etc.

Thanks for the suggestion, I'll try your method to see how it works