OS X Yosemite -- Why Are Some Finder Icons Black Squares?

[Sirentist]

I make custom stencils and ArtRage always has been my go-to program for this. Here's a question I've had for years (I hope I've posted it in the right forum area): Sometimes my saved paintings display in the finder as black squares instead of looking like thumbnails of the art in the painting itself. Other times, they do display correctly as whatever layers I have visible in the painting. Anyone know why, and how to change it so it always displays a thumbnail instead of a black square?

I'm sure it's some stupid setting I have somewhere, but I've never been able to figure it out!

Thanks in advance for any help/advice.



Other, possibly relevant, information:

I work on a late 2014 iMac Retina 5k, 27-inch, OS X Yosemite version 10.10.1.
I'm using ArtRage Studio Pro 3.5.12.
My .ptg files typically involve many hidden layers.

[HannahRage]

Are the black squares from paintings with transparent backgrounds? Sometimes transparent PNGs show up as black.

If not, is it always the same paintings? Or does it change?

[Sirentist]

Oh, wow, you're right! It's related to transparent backgrounds. As soon as I stuck a new layer above the transparent background and filled that layer with white, then saved the file, the thumbnail changed. Sometimes I have to save and close and reopen and save again to get the change to "stick," but it's definitely the transparent backgrounds. Yay! Thank you! You've just revolutionized my filing system, now that I can finally SEE the darn things.

[HannahRage]

Oh good, I am glad that is solved!