How to fade two images together in Sketch

Question 1

get rid of seem?

Is it possible in Sketch3 to do a mask w/ a gradient to make these two images seemless? Basically this technique (for photoshop) http://www.wikihow.com/Fade-One-Image-Onto-Another-in-Photoshop

…how do I do this in Sketch 3?

Question 2

This is possible.

Insert a rectangle around the first image.
Select both rectangle and image, and mask it: Layer / Mask with Selected Shape.
Select the Mask and switch it to Alpha Mask: Layer / Mask Mode / Alpha Mask.
Fill it with a Linear gradient, set the start color to transparent and the
end color to black.
Adjust the angle of the gradient from top/bottom to left/right.
Do the exact same for the second image, but set the angle of the gradient right/left.
Move the second image slightly on top of the first image.

And voila:

enter image description here

Answer