Scale an Image in Photoshop Without Stretching (Content-Aware Scale)
When standard transforms stretch important subjects, Content-Aware Scale can protect them while resizing. You’ll duplicate your layer, save a selection of key elements, crop to the target aspect ratio without deleting pixels, and scale with protection enabled. Finish with a quick patch if any areas distort.

Step-by-step instructions
Prepare a duplicate layer
Duplicate the image layer: Layer → Duplicate Layer (or press Ctrl+J / Command+J).
Disable the Background layer by clicking its eye icon to work non-destructively.
Create and save a protected selection
Use the Lasso Tool to select important elements (e.g., the woman in red).
Hold Shift and add other key subjects (e.g., the Eiffel Tower and parts of the bridge).
Go to Select → Save Selection, name it (e.g., “Woman and Tower”), and click OK.
Go to Select → Deselect.
Crop to a 9:16 portrait without deleting pixels
Select the Crop Tool and set the ratio to 16:9, then click the double-sided arrows to swap to 9:16.
Uncheck Delete Cropped Pixels in the options bar.
Position the crop and press Enter/Return to commit.
Scale with Content-Aware Scale and Protect
Go to Edit → Content-Aware Scale.
In the options bar, set Protect to your saved selection.
Drag the handles to scale so the image fits while protected elements remain undistorted.
Press Enter/Return to apply.
Optional: Patch stretched areas
Re-enable the original image layer (click its eye icon).
With the Polygonal Lasso Tool, select a clean area of ground from the original.
Press Ctrl+J / Command+J to copy the selection to a new layer.
Use the Move Tool (V) to position the patch where needed.