Here you can find screen caps from the Anime Series as well as the Theatricle Short.
The anime screen caps are currently ordered by charater becuase right now, I don't have time to re-watch the whole series and match captures with an episode. Similarly, the movie screen caps are not in order either.
Massive thanks to Byasama for donating most of this captures, and to Yuuki Hikaru for donating others.

ANIME SCREENCAPS

Hamel Village Boy Embarressed Go Towards the Light! Brooding In the Shadows Ready to Spring Musical battle Playing at the Village The Horn Demon Blood I Am Human	Sizer As a Child Seeing Mom Looking Up Determined Sizer and Ocarina More Crying Sizer Poses Sizer and The Box	Flute Surprised Princess Sad Peincess Cloaked Determined Accepting Realization Hugging the Box	Raiel Surprised Cheerful Pretty Serious	Pandora and Chestra Pandora Holding the Box Pandora Released In the Crystal Pleading Demon King Husband and Wife
Trom Cute Stunned Charge! All Grown Up	Horn Angry Overjoyed Monarch	Bass Deadly The Head Smirk Confident Profile	Misc Guitar Coronet Obo Ocarina	Groups Flute and Hamel Sizer and Raiel Child Raiel and Hamel Sizer, Flute, and Guitar Freeing Lute 1 Freeing Lute 2 Freeing Lute 3

MOVIE SCREENCAPS

Sizer Hamel Cute Hamel Lecture Flute Smash! Raiel and Sizer	Hamel Psychotic Hamel Serious Sizer Flying Demons Flute Cute	Raiel Screaming Flute Dog Sizer Dog Flute Power Up With Friends Like These	Four Heros Bass The Great Hero? Flute's Temper Flute and Hamel	King Hamel To the North!