Like A Frame has had the Rounded Corners ever since the beginning, but it was always constrained to rounding off all of the corners at once—the frame, the matte and the photo itself proportionally. In version 6.4, you’ll now see a new Sharp Photo Corners toggle which maintains sharp corners on the photo whilst changing the way the rest of the matte and frame are rounded.

This finally enables the app to achieve Polaroid-style images in one layer (plus some text if you desire). You may need to shift the photo within the matte when editing the Photo Matte thickness by dragging on the canvas.

How to achieve a Polaroid-style image:

Create a new canvas with your photo of choice.
Open the Photo Matte setting and adjust the thickness of the matte you’d like around your photo.
Open the Rounded Corners setting and turn on Sharp Photo Corners toggle then adjust the radius of the corner rounding.
Go back to the Photo Matte and drag with your finger to adjust the placement of the photo inside the matte.
Add a Frame Shadow, set the canvas background and text layers as desired.