The church is not covered with mosaic, it was painted during the XVIth century.
Still, I'll be your Google. Here is what I have found:
Gura Humorului is located in the north-eastern part of Romania, in southern Bukovina. The town is situated at the eastern limit of Obicinele Bucovinei mountains, in Humorului Depression, at the confluence of Moldova River and Humor River. The average altitude of the town is 470 meters.

Founded in 1530, Humor is rather small physically, but looms large among Bucovina's treasures with a variety of frescoes dating from 1535, including one illustrating the Return of the Prodigal Son and one with a "humorous" depiction of the devil as a woman.

The church, topped by a cross-shaped shingled roof, is without a steeple, indicating that it was built by a court official rather than a prince. The predominant hues of the frescoes are reddish brown with some rich blues and green infusions.

Unfortunately the painted churches in NW Romania are slowly decaying. Their restauration would cost a fortune which does not exist there. Moreover, they have not found the composition of the famous blue coulour yet...

A surprise, I cant' wait! Love surprises, hope it is a good one