Stop Frame Corner Stretching?

[Frostorm]

So I recently decided to change my window skin, as in making my own from scratch. I used to use a gradient-based window skin so the stretching of the border (when a window is very rectangular) wasn't an issue. But now I'm going for a more image-based skin so the stretching makes it look really bad. Are there any known workarounds for this?

Edit: Hmm, it seems like the 1st 24 pixels or so don't get stretched, though I'm having a hard time confirming...is this truly the case?

 

[Ahuramazda]

When the game makes a window it "patches" the windows together from the outside sections



the for 24x24 corners should never stretch, but then anything in the middle 24x48 section will be used over and over as needed to make the proper width/height of the window... so unless you have a skin that can look uniform every 24 pixels or whatnot and image based window skin might be tricky.

At least this is how I came to understand how the window border was created... if Im wrong someone can correct me

 

[Frostorm]

Hmm, yea that makes sense. The only other explanation I thought of was that maybe it's using 9-slice scaling. In any case, it seems I'm limited to 24x24 if I want to use an image. Does anyone happen to have a workaround? I wanted to use something along the lines of these: