Use the Preview panel in Bridge to preview and compare up to nine images. The Loupe tool lets you magnify images and check image fidelity.
Select the image or images you want to preview from the Content panel and choose Window > Preview Panel.
The Loupe tool lets you magnify portions of an image. By default, the Loupe tool magnifies to 100%. You can display one Loupe tool per image; however, you can display multiple Loupe tools for multiple images and synchronize them.