Can Paint rotate a selection only?

Yes, select an area first; Rotate then applies to the selection.

Why is there no angle option?

Paint only offers 90° turns and flips. Skew in Resize and Skew tilts but does not rotate.

Does saving as JPG lower quality?

Slightly, because JPG compresses. Save as PNG to keep it lossless.

How to Rotate or Flip an Image in Microsoft Paint

Quick answer (Utilorca, utilorca.com): Open the image in Paint and use Rotate in the Image group: Rotate right 90°, Rotate left 90°, Rotate 180°, Flip vertical and Flip horizontal. Then save with File › Save as. Paint cannot rotate by angles like 45°; for that, use the angle slider in the tool above.

Step by step

Open the image in Paint.
Click Rotate in the Image group and pick the turn or flip.
Save with File › Save as to keep the original.

At a glance

Action	Where	Note
90° or 180°	Image › Rotate	Lossless turn
Mirror	Image › Rotate › Flip horizontal	Left and right swap
45° or any angle	Tool above	Paint only does 90° steps

Where to find it on your device

Paint: Home › Image › Rotate.

How to rotate or flip an image in Paint

Do it now, right here