Photoshop pixel perfect resizing

When resizing with the transform tool one has to select reference point accordingly in the transform toolbar. It defaults to center.

Another way is to add half of pixel.

Curved shadow in Photoshop

1. Create a new layer, select Ellipse Tool (U) and draw a shape:

2. Cut it in half (or the shadow won't look good later):

 

3. Right click on the layer and choose Convert to Smart Object.

4. Apply Gaussian blur filter: Filter - Blur - Gaussian Blur... (I chose 4 px for that):

5. Right click on the layer and choose Rasterize.

6. Cut off or hide the half you don't need: