Yay! Here's an image that works!
The arrow is 100% opaque and the background is 50% transparent (nice feature to not block the view 100%).

The arrow should be pointing exactly 45 degrees to the left when in 16:9 resolution and the green background should be a perfect square.

I think the size of the background is pretty good cuz it's small enough not to be in the way. Place it x=0 and y=0.75 and you got the position right

Just need better looking arrows.

The recipe I used was:
create an image of size 128x128
draw an arrow on it
squish it to 72x128
copy it to the center of an image 256x256.
Voilla perfect proportions in 16:9 aspect ratio

Lol!
Missed your post! Sure shapes without backgrounds sounds good as long as they are clearly visible regardless of the in game content behind the signs. (Day sky, night sky, blinding light, platforms. canyons).
Eager to see what you have in mind.
If you need help with a new stretching recipe just let me know and I'll do the math.

stretching is no problem, i did that before. but as i said, you'll have to wait a few days.
(i'm just on mobile, cant do anything)

Hey!
You're the person behind the wooden sign pack! Really nice signs

Yikes! To think I showed you that ugly arrow on green background.

Really glad you took interest in the idea. This is getting exciting.

lol no problem. but no promises!

No pressure, no pressure

first little test: transparency in png is no problem at all, file is even much smaller than dds.

Agreed
PNG seems to be the best choice.
Have you had time to try out your ideas some more?
*nosilly peaking over doben's shoulder*

just tested a bit, but didnt elaborate anything. i'll be on a spontaneous holiday over the next few weeks, anyway, so no updates there. sorry