Open the image in an editor that supports DPI settings
Check the current image resolution and print size
Go to Image Size or Resize settings
Disable resampling if you only want to change DPI metadata
Enter the desired DPI value
Keep or adjust the pixel dimensions if needed
Enable resampling if you need to increase actual print quality
Choose a resampling method such as bicubic or Lanczos
Save the image in a format that preserves DPI settings
Reopen the file to confirm the updated DPI value