I'm trying to frame an image for an upcoming juried show. It's a square frame from my Holga, and I was planning to make a 12x12 C print. I've "staged" several options using American Frame's online tool, but nothing looks quite right. I tried a 16x16 square frame, but it looks just too square (if that makes sense). I thought that offsetting it to the top of a rectangular frame (say 16x20) might work better, but now I'm not so sure. Should I center it vertically in a 16x20 frame? I know this is subjective, but maybe hearing what other people prefer for square images would help. The requirements are a black metal or wood frame, and a white, off-white or black mat without ridiculously large borders.

Here's the image:

Thanks in advance.