Why Image Size, DPI, and File Format Matter for Print

Streamline your print production with ease by ensuring your images are print-ready from the start. When clients send images for book covers or inside pages, confusion often starts with things like pixels, DPI, and file formats. An image might look fine on your screen but still not work well for print. This does not mean the image is bad or unusable. It just means it was made for screens, not for printing. Many images from clients are phone photos or downloaded from the internet, and these can cause copyright problems if the usage rights are not clear. That is why I prefer to use images from stock sites, where the licensing is simple. Sometimes we also make artwork with AI programs like ChatGPT or Gemini, but those files still need to be prepared for print. This includes upscaling if needed, careful cropping, and final adjustments to make sure they print well.

Most images from websites or made for online use are set to 72 DPI. Think of it like a postcard, perfect for viewing on a screen because it keeps files small and quick to download. But printing requires something more akin to a billboard of detail. For print, images should be set to 300 DPI (dots per inch), as this setting affects how much detail appears on paper. Pixels show how much information is in the image, while DPI tells you how closely that information is packed when printed.

This is where people often get confused. For example, an image that is about one thousand pixels wide at 72 DPI can look big on your screen. To see why the size shrinks, consider the calculation: 1000 pixels ÷ 300 DPI ≈ 3.3 inches. If you change it to 300 DPI without adding more pixels, the printed size gets smaller. No data is lost. The pixels are just packed closer together, so the image prints with enough detail. That is why a web image can look much smaller when you get it ready for print.

should usually be cropped closely, without a big square background. A large white box can make layout alignment awkward and may lead to unnecessary ink waste during printing. Taking away that empty space makes it easier to place the element in a layout and scale it properly. After cropping, the file might look smaller, but it is actually more accurate and better for print.

File format is important too. I usually save these elements as PNG files. PNG supports transparency, so there is no background in the image. Picture placing a white JPEG logo on cream paper and seeing a pale ghost box around it—that's when PNG transparency becomes valuable. This lets you place the graphic on white, beige, or textured paper without a visible box around it. JPEG files do not support transparency and always have a solid background, usually white. On off-white or textured paper, that background can show up. PNG also keeps edges cleaner for small details because it does not use the same compression as JPEG.

You can also artificially increase an image’s resolution. This is easy to do in Photoshop. However, upscaling does not add real detail. The software makes new pixels based on the ones already there. On screen, this often looks fine, but in print, it can cause softer edges and less sharpness. A smaller image set up correctly at 300 DPI will usually print better than a larger image that has just been enlarged.

Comparison of Image Quality: A 72 DPI low-resolution image appears pixelated, while a 300 DPI high-resolution image is clear and detailed, illustrating the impact of dots per inch on visual clarity.

At 300 DPI the pixels are packed tightly, which is what print needs.

When I get images ready for print, I do not focus on a specific pixel count. My goal is to make sure the file prints clearly, keeps important details, and fits well into the final layout. If you are ever unsure if an image will work for print, it is always best to check before production. This usually saves time and helps avoid extra revisions later.

Before you hit print, ask yourself these three quick questions:

1. Is the image resolution set to 300 DPI for optimal print quality?

2. Have you ensured that the file format supports the desired design elements, such as transparency?

3. Did you verify the image's copyright and usage rights to prevent any legal issues?