How to Fix Email Signature Images Changing Size

How to Fix Email Signature Images Changing Size

Are your email signature images changing size or showing much larger when you install the signature in your email client?

The most common reason for email signature images changing in size is because the image resolution (in DPI) is not set to 72 DPI, or 96 DPI for older versions of Outlook (2016 and earlier).

If your DPI settings are too high, you’ll likely end up with an enlarged image in your email signature. 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 DPI setting on the image.

Let’s take a look at what DPI is and how you can fix this issue.

What is DPI?

DPI stands for Dots-Per-Inch. Also referred to as PPI or Pixels-Per-Inch. It is used to measure how many dots (or pixels) will be used in a line which is 1 inch in length.

pixels per inch explainer

DPI is primarily used to determine the quality of a document which is going to be printed. However, some email clients, mainly Outlook and Apple Mail use DPI to measure the resolution of images, instead of simply using the height and width of the images.

Image DPI Recommendations for Email Signatures

In order for the images in your email signature to display correctly, you will need to use the following DPI settings depending on which email client you’re using.

  • If you’re using older versions of Microsoft Outlook (2016 and earlier), the DPI of the image should be 96 DPI.
  • For all other email clients, the DPI of the image should be 72 DPI.

If you have an image in your signature that has a DPI of lets say 300, the image will probably look very big.

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


How to Change the DPI of an Image Using Photoshop

Step 1

Open your image in Photoshop.

photoshop open file

Step 2

Click on Image > Image Size.

photoshop image size

Step 3

In the Resolution field, enter the new DPI value that you want to use:

  • 96 DPI for older versions of Outlook (2016 and earlier)
  • 72 DPI for all other email clients

Ensure that the measurement is set to “Pixels/Inch” and 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.

photoshop save image

Other Ways to Change the DPI of an Image

If you dont have Photoshop or any other image processing software, you can easily change the DPI of your images using Clideo or Convert Town, both of which are free tools.

9 Replies to “How to Fix Email Signature Images Changing Size”

  1. Unfortunately this still doesn’t work… The image is now still massive and now just blurry, despite reducing to 72 dpi and ensuring it’s a .jpeg file.

    Disappointing… ?

  2. Outlook for Mac still has this issue (v16.50).

    It doesn’t always happen but when you send out mail with your signature properly set and email is received, you scroll down to see your signature as massive. Changing the DPI does not work either.

    1. I’ve been googling for an hour on how to change this with no solutions. Outlook sucks so hard.

    2. I thought I had solved my issue after I changed my signature logo to 96DPI. Most of the time, replies to my email come back the same size. But still, every now and then, …BAM! I scroll down to see that my logo is now the size of the page! I am using outlook on an Apple laptop.

  3. Yup, like others, my email signature card is set to 3.5″ by about 2″ and looks proportional when I hit “send.” But when some people get it, it’s massive and takes up a quarter page, when some people get it, it’s about right. When they Reply, and I get it back, it’s tiny and you can’t even read the verbiage. This has all been when the PPI (I use Mac Mail and it’s pixels per inch, not dots per inch!), and it was set at 144. So I changed it to 72 PPI as suggested and now the image appears to be the right “size” but the verbiage is fuzzy and nearly unreadable and the quality of the image is horrible. I’ve spent 5 hours on this and inconvenienced friends by constantly sending them test emails, so frustrating!!!!!!! 🙁

  4. So it works with copy and paste! After adjusting the image to the proper size, just copy and paste it in the signature box. This prevents the image from changing size!

  5. How does this work with copy and paste? I have my image in Outlook at 96 dpi as required, pasted into in the signature box and it looks fine in my email, but when we get replies, the images are enlarged. Doesn’t make sense ??

  6. This might help explain things:

    I was able to set up the signature with html to look proper before sending, but the image would be large after receiving. Seems like Outlook doesn’t handle the image (resize) [css] properly.

    So, I had an image that was sized at 360×100 and I was trying to size it close to 160×50, so I:

    – Downloaded the image.
    – Using GIMP, scaled the image to 180×50.
    – GIMP > Image > Print Resolution: change X & Y resolution to 96 pixels/in.

    Now, the image is appearing as I expected in the receiving end of the signature.

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