How to fix email signature images changing size?

Are your email signature images changing or showing much larger when installing the signature in your email client?

For the images in your email signature to display correctly, you will need to use the following DPI settings depending on your email client.

  • If you're using Microsoft Outlook, the DPI of the image should be 96 DPI.

    email signature outlook

  • If you're using Apple Mail, the DPI of the image should be 72 DPI.

    apple mail email signature

If you have an image in your signature that has a DPI of, let's say, 300, the image will probably look very big. This happens because Microsoft Outlook and Apple Mail scale images using the DPI value.

To fix this, you will need to use an image processing tool such as Photoshop to change the image's DPI setting.

How to check the DPI of your images

The simplest way to check the DPI of an image in Windows is to right-click on the image > Properties > Details tab and check the DPI value.

Note: This method only works on some image types and will not work on PNG images.

You can also check and change the DPI of an image using almost any image processing software, such as Photoshop.

How to change the DPI of your images using Photoshop

Step 1.
Open your image in Photoshop.


Step 2.
Click on image > Image Size.

Step 3.
In the Resolution field, enter the new DPI value you want to use (96 DPI for Outlook or 72 DPI for Apple Mail) and ensure that the measurement is set to "Pixels/Inch".
Also, ensure that Resample: Automatic is ticked.


Step 4.
Save your image
and use it in your email signature.
Now that the DPI has been changed, this should stop it from scaling up in size.

Are You Ready to Create Your Email Signature?

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Ostap is a marketing professional (PMM) with 5+ years of experience in the software industry (B2B and B2C). Having worked with email marketing products and services, Ostap has a deep understanding of various email marketing strategies and solutions.