There are two ways that you can change the size of a picture (picture: A file (such as a metafile) that you can ungroup and manipulate as two or more objects or a file that stays as a single object (such as bitmaps).) — resizing and cropping.
Resizing changes the dimensions of the picture by stretching or shrinking it.
Cropping reduces the size of the picture by removing the vertical or horizontal edges. Cropping is often used to hide or trim a part of a picture, either for emphasis or to remove unwanted portions.
You can also outcrop, which adds a margin around a picture.
You can always restore a resized or a cropped picture to its original size. If you're certain you won't want to undo your work, then after you crop the picture, use the Compress Pictures feature to delete the cropped parts of the picture from the file completely.