HOWTO | Master working with images in Pages
Go to File > New > Blank template. Add some text (if you add placeholder text from lipsum.com, temporarily disable spell-checking in Edit > Spelling and Grammar). Drag an image over from Finder or add one by clicking the Media button and then selecting from Photos or from an album.
Arrange your image
Drag your picture to move it. Guides appear when it’s central or aligned to page margins. Dragging a corner handle resizes the image (in proportion, if Constrain Proportions is checked in the Format Inspector’s Arrange tab). Rotate/flip your image using the controls in the Rotate section.