Good day Keanu Estrada,
If this is Microsoft Photos on Windows, temporarily change Settings > System > Display > Scale to 100% or the recommended value, then restart Photos and test again.
This workaround has helped users because custom display scaling can cause Photos to calculate the editing preview incorrectly, making the screenshot appear smaller even though its actual dimensions have not changed. If it works, restore your preferred scaling afterward and report the issue through Feedback Hub > Apps > Photos so the relevant product team can investigate it, as this is a workaround rather than a permanent fix. Since this is a user-to-user forum, we cannot investigate the Photos app’s internal behavior or forward the issue directly to the product team.
Thank you for your patience!