DPI or “dots per inch” is a way of measuring an image's original intended size and its resolution, or quality. DPI is a measurement of dots per inch of printed or monitor-viewed image. The higher the dpi, the higher the resolution, and the better the image quality. Most Stock Photo Agencies offer Stock Photos to buy from 72 dpi to 300 dpi. We recommend to buy the highest resolution you can get. You always can change the DPI from 300 dpi to 72 dpi in any common image editing software like Photoshop.
What is the right DPI for your project?
When dealing with images, there are two basic standard DPI measurements to look for. If you plan to print an image, you need a resolution of at least 300 dpi. For online use, you should look for an image resolution of 72 dpi or higher.
You can go smaller, not bigger
DPI also indicates an image's maximum size. It's important to remember that digital images will only maintain their quality and resolution if they are reduced in size. Images should never be stretched, or made larger. If an image is too small for your intended use, just look for a larger image with a higher dpi value.