Understanding DPI & How to Improve Photo Quality for Print

What’s included in this article?

1. What is DPI, and why does it matter?
2. Can changing DPI improve image quality?
3. How to check if your image is high enough quality
4. How to find your image file size and dimensions
5. How image size affects print quality (with examples)
6. How to change DPI (if needed)
7. Best programs to adjust DPI
8. What to do if your image is too small

What is DPI and why does it matter?

DPI (dots per inch) refers to how many pixels are printed within one inch of your image. For high-quality printing, we recommend 300 DPI.

Higher DPI = more detail in print
Lower DPI = less detail, which can result in blur or pixelation

Can changing DPI improve image quality?

No. Changing the DPI alone does not improve image quality.

DPI is simply a setting that tells a printer how to scale your image. It does not add detail or increase resolution. If your image has a low pixel count, increasing the DPI will not make it sharper.

How to check if your image is high enough quality

Image quality depends on both:

• Pixel dimensions (width × height in pixels)
• Print size

If your image is too small for the space it’s placed in, you may see a low-resolution warning in the editor. This typically appears when:

• The image is below ~150 DPI at the size used
• The image dimensions are smaller than the photo box

For best results, your image should be large enough to display at 300 DPI at the intended print size.

How to find your image file size and dimensions

To determine if your image will print well, you’ll want to check:

• Pixel dimensions (width × height in pixels)
• File size (KB or MB)

On a Mac

1. Right-click the image file
2. Select Get Info
3. Look for:
   • Dimensions (e.g., 4032 × 3024)
   • File size (e.g., 2.5 MB)

OR

1. Open the image in Preview 
2. Click Tools at the top 
3. Show Inspector 
4. Look for: 
   • Image Size (e.g., 4032 × 3024 pixels)
   • Image DPI (e.g., 72 pixels/inch)

On Windows

1. Right-click the image file
2. Select Properties
3. Click the Details tab
4. View:
   • Dimensions
   • File size

On an iPhone

1. Open the Photos app
2. Select your image
3. Tap the info (ⓘ) icon or swipe up
4. You’ll see:
   • Image dimensions
   • File size

How image size affects print quality (with examples)

Example 1: iPhone photo

Most modern iPhone photos are around 4032 × 3024 pixels at 72 DPI.

Even though the DPI says 72, this image can print at:

• 13.4" × 10" at 300 DPI (high quality)
• 20" × 15" at ~200 DPI (still good quality, slightly softer)

So while the file says 72 DPI, it actually contains enough detail for large, high-quality prints.

Example 2: Image from social media

Images downloaded from platforms like Instagram or Facebook are often reduced to around 1080 × 1080 pixels.

This means:

• 3.6" × 3.6" at 300 DPI (best quality)
• Anything larger may appear blurry or pixelated

Example 3: Small image file

If your image is 800 × 600 pixels:

• 2.6" × 2" at 300 DPI (sharp)
• Printing larger will likely result in visible pixelation

How to change DPI (if needed)

If your image is already high-resolution, you can adjust the DPI setting without affecting the quality.

Important: Make sure “resample” is turned off to avoid altering the image data.

General steps:

1. Open your image in an editing program
2. Locate the Image Size or Resize settings
3. Uncheck Resample
4. Change the resolution to 300 DPI
5. Save your file

This will not increase quality, but it ensures your file is set up correctly for printing.

Best programs to adjust DPI

You can update DPI settings using most image editing tools:

• Adobe Photoshop – Image > Image Size
• Preview (Mac) – Tools > Adjust Size
• Adobe Lightroom – Export settings
• Canva – Export with high-quality settings (300 DPI equivalent)
• GIMP (free) – Image > Print Size

What to do if your image is too small

If your image appears blurry or shows a low-resolution warning, adjusting DPI will not fix it. Instead, we recommend:

• Locating the original file (from your camera or device)
• Avoiding images downloaded from:
  • Social media (Facebook, Instagram)
  • Screenshots or text messages
• Requesting a higher-resolution version from the photographer
• Exporting the image again at full size from your editing software