Before you download your stock photos, it's important you check that the images you've chosen are big enough. You need to consider:

• the resolution or dpi
• the dimensions

The dimensions listed on our site indicate the size that your image will appear when printed, and the resolution indicates how much detail will be included in every inch printed – dots per inch (dpi). As a rule, it's 300dpi for print and 72dpi for web.

Large format prints, such as billboards, are usually printed at lower resolutions of under 150dpi (the image is less detailed because it is viewed from farther away) although it's worth checking with your designer before you start.

Our royalty free images are priced by file size, generally the larger the file the higher the cost. It's easy to downsize an image without compromising quality, but if you buy an image that's too small the quality will be affected if you try to make it bigger.

We want you to get value for money, so if you're not sure what size you need, get in touch.

Here's a rough guide to help:

© Juniors Bildarchiv / Alamy