TESTED · IMAGE WORKFLOWS
Crop a photo to 16:9 in Windows without cutting off the subject
Use Photos crop controls and downloadable examples to distinguish aspect ratio, crop placement, resizing and exact pixel requirements.
To make a photo 16:9 without losing the subject, choose the ratio first, then move the crop frame to protect what matters near the edges. A centered crop is convenient, but it is only one possible placement.
In Windows Photos, open the image, choose Edit image (or press Ctrl+E), select Crop, choose a 16:9 aspect ratio preset where available, and reposition the image within the crop. Microsoft also documents Reset for undoing edits. Keep your original and save or export a separate copy where that option is offered. Microsoft’s Photos editing instructions describe the controls; the examples below show what different crop positions do to the same image.
Check the edges before you crop
This original 1200 × 900 image has a yellow subject box near the lower right. Its box extends from roughly x=835 to 1160 and y=620 to 860. That lower edge is the detail to watch as the frame changes.

The inline pictures are smaller display previews. The download links provide the full original files used for the measurements.
At a width of 1200 pixels, a 16:9 crop must be 675 pixels tall: 1200 × 9 ÷ 16 = 675. The original is 900 pixels tall, so the crop removes 225 rows. Where those rows come from determines whether the whole yellow box survives.
A centered crop removes 112 rows from the top and 113 from the bottom. It keeps rows 112 through 786, ending at y=787. The yellow box reaches y=860, so this placement cuts off its lower portion.

Download the centered crop to compare it with the original. Both files are 1200 pixels wide, but the cropped file is 675 pixels tall.
Moving the crop to the bottom removes all 225 rows from the top instead. It retains rows 225 through 899, including the entire yellow box. The pink circle, which lies between y=230 and y=545, remains in both crops.

Download the bottom-aligned crop. Before committing a 16:9 crop, inspect important details close to all four edges. Move the frame deliberately, then check those edges again.
Crop placement versus a stretched image
Cropping changes which part of the image is kept. It does not have to change the shape of anything inside that area. The two crops above retain the original pixel geometry of the pink circle.
Stretching the entire 1200 × 900 image into a 1200 × 675 frame also produces 16:9 dimensions, but it compresses everything vertically. The vertical scale is 675 ÷ 900, or 75%, while the horizontal scale stays at 100%. The circle becomes flatter:

Download the stretched example if you want to compare it directly with the crops. For this image, moving a crop frame preserves both the lower label and the circle’s shape; forcing the full image into the target dimensions does not.
Padding is another option when every edge of the original must remain. Instead of discarding rows, it adds space around the image. For example, a 1200 × 900 image would need a 1600 × 900 frame to have a 16:9 outer shape, leaving 200 pixels of added space on each side if centered. That is useful when retaining the entire picture matters more than filling the frame with image content.
Check the saved dimensions
An aspect ratio and an exact pixel size are separate requirements. Cropping the example at its full available width gives 1200 × 675. If a destination asks for 960 × 540, both sizes are 16:9, but the crop alone does not produce the smaller file. The 1200 × 675 result would also need to be resized to 80% of its dimensions.
The same arithmetic helps with a larger photo. At 4000 × 3000, the largest 16:9 crop that keeps the full 4000-pixel width is 4000 × 2250. That leaves 750 vertical pixels to remove. Decide which content must remain before positioning that crop.
The same source also has a right-aligned square crop, made by keeping columns 300 through 1199 and all 900 rows. Its saved size is 900 × 900. Moving the square right preserves the lower-right label, but it cannot produce a native 1080 × 1080 square: the source supplies only 900 pixels of height. Enlarging the result would be an additional operation.
For another ratio, divide the proposed width by that ratio to get the required height. A 1200-pixel-wide 16:9 frame requires 1200 ÷ (16 ÷ 9) = 675 pixels of height. If the required height exceeds the available source height, keep the height instead and multiply it by the ratio to find the maximum crop width. That arithmetic tells you the available frame before you choose its position.
After saving, check the file’s width and height, then reopen the saved image. If a website preview looks cropped but the downloaded or uploaded file still has its original dimensions, the site may only be displaying it inside a 16:9 display frame. The preview does not by itself prove that the stored file was cropped. Check the saved file you intend to use.
Example scope: The linked images come from original synthetic artwork processed with Pillow 12.3.0. The two 16:9 examples are native-pixel crops with no resizing; the stretched file illustrates resizing instead. The Photos steps come from Microsoft’s instructions, and no native Photos editing session was recorded.