Resize an image to different pixel dimensions. Use the target platform's required width, height and aspect ratio to choose a sensible output.
Image dimensions and file size are different. Reducing a 3000 × 2000-pixel image to 1500 × 1000 pixels retains its 3:2 aspect ratio; stretching it into a square without cropping changes proportions.
If you need a particular framing, crop the original before or after resizing. Enlarging a small image cannot recreate detail that was not captured in the original.
Do not confuse pixels with print resolution. Check the output dimensions and inspect faces, logos and text at the size where the image will actually be used.