Royal Naval College, Greenwich

Help With Image Sizes

Bigstock offers our photos and bitmap illustrations at different image sizes.

What size do I need?

• Choose a large or extra-large image for a project that will be printed on a full page or at poster size.
• Choose a medium-size or large image if you're printing the image on less than a full page.
• A small image is best for a web site or another computer-based presentation.

All Bigstock photos can be resized with common image editing programs such as Adobe Photoshop. When in doubt, choose a larger size. You can always make a large image smaller, but if you start with a small image and enlarge it or significantly crop it, your image may look jagged or blurry.

What are pixel dimensions and megapixels?

Image sizes are presented in two ways: pixel dimensions and megapixels. Both these measurements describe the quality of the digital image file is; the more pixels, the sharper the image. Medium images are normally 1200 pixels on the longest side (and typically 1.1 megapixels). Large images can be up to 4500 pixels on the longest side (ranging from 1.5 megapixels to 14 megapixels).

What is DPI?

Bigstock images are also labeled with a Dots Per Inch (DPI) number, usually either 72 or 300. DPI is a printing setting that indicates how sharp the image will be (ie., how many pixels per inch) when printed. You can change an image's DPI in Photoshop without affecting its overall quality.

Typically, images meant for a high-quality print project are set at 300 DPI, while images meant for viewing on a computer screen are set at 72 DPI.

This table shows the maximum dimensions at which you can print an image at 300 DPI (high quality printing) and 150 DPI (lower-quality printing). The dimensions listed here are typical examples and will vary from image to image.