Ok guys, I'm pulling my hair out and have tried way too much to remember.

Basically I'm having the age old issue with a solid black being shown on third party HD icons.
I have posted a few images from different themes (The only way I have managed to successfully get rid of it was for the futurama theme, but that doesn't help me with full size rounded rectangle icons.)

As you can see I'm close with the simpsons theme but there's still a black line.

I want to make hd icons similar to the black and white icons but as you can see the stock ones are bigger and the third party are a different shape. (I'm happy to have the stock ones the same size as the third party if that helps)

someone please help