Print the exception on thumbnail creation failure
Print the exception on thumbnail creation failure

Fixes #922

getnikola/nikola,berezovskyi/nikola,wcmckee/nikola,schettino72/nikola,immanetize/nikola,pluser/nikola,atiro/nikola,jjconti/nikola,gwax/nikola,schettino72/nikola,TyberiusPrime/nikola,knowsuchagency/nikola,andredias/nikola,x1101/nikola,s2hc-johan/nikola,lucacerone/nikola,lucacerone/nikola,berezovskyi/nikola,getnikola/nikola,okin/nikola,xuhdev/nikola,s2hc-johan/nikola,JohnTroony/nikola,yamila-moreno/nikola,knowsuchagency/nikola,yamila-moreno/nikola,JohnTroony/nikola,x1101/nikola,xuhdev/nikola,pluser/nikola,getnikola/nikola,TyberiusPrime/nikola,xuhdev/nikola,lucacerone/nikola,okin/nikola,xuhdev/nikola,atiro/nikola,atiro/nikola,techdragon/nikola,okin/nikola,gwax/nikola,andredias/nikola,techdragon/nikola,andredias/nikola,gwax/nikola,masayuko/nikola,techdragon/nikola,TyberiusPrime/nikola,immanetize/nikola,jjconti/nikola,wcmckee/nikola,schettino72/nikola,JohnTroony/nikola,yamila-moreno/nikola,wcmckee/nikola,knowsuchagency/nikola,jjconti/nikola,getnikola/nikola,pluser/nikola,s2hc-johan/nikola,berezovskyi/nikola,okin/nikola,masayuko/nikola,x1101/nikola,masayuko/nikola,immanetize/nikola