When using images in a document, the document can become very large if the images are used in full size. It can cause problems if the document needs to be sent as an email or if it needs to be printed.

Reduce the file size of a picture in Microsoft Office, eg. Word or PowerPoint.

Crop a picture in Office.

Change the brightness, contrast, or sharpness of a picture.

Change the color of a picture.

Edit photos and videos in Photos app.