You can subscribe to the image editor subscription to get access to a built-in image editor, or you have receive the addon for free if your subscription tier is high enough.
How to access the image editor
The images you want to edit must be uploaded already.
Select your image and press in the action bar on edit:
The image editor will open full screen.
You can revert all edits with the clock button top left:
Press the Done button to save as a copy or to overwrite the original image in your drive.