To edit photos from the Dropbox mobile app:
- Tap to preview the image you want to edit.
- Tap the pencil icon to enter Edit view, where you can crop or rotate your image.
Crop an image
- From the Edit view, tap the Crop icon.
- Drag the border that appears on your image to resize the crop boundary. You can also tap from inside the boundary to move the entire crop boundary.
- When you're satisfied with the crop, tap the check mark icon.
- Tap Save.
Rotate an image
From the Edit view tap the Rotate icon until the image is in its desired orientation.